Currently the size of one sub buffer page is global for all buffers and
it is hard coded to one system page. In order to introduce configurable
ring buffer sub page size, the internal logic should be refactored to
work with sub page size per ring buffer.
Link: https://lore.kernel.org/linux-trace-devel/20211213094825.61876-3-tz.stoyanov@gmail.com
Link: https://lore.kernel.org/linux-trace-kernel/20231219185628.009147038@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
A trace instance may only need to enable specific events. As the eventfs
directory of an instance currently creates all events which adds overhead,
allow internal instances to be created with just the events in systems
that they care about. This currently only deals with systems and not
individual events, but this should bring down the overhead of creating
instances for specific use cases quite bit.
The trace_array_get_by_name() now has another parameter "systems". This
parameter is a const string pointer of a comma/space separated list of
event systems that should be created by the trace_array. (Note if the
trace_array already exists, this parameter is ignored).
The list of systems is saved and if a module is loaded, its events will
not be added unless the system for those events also match the systems
string.
Link: https://lore.kernel.org/linux-trace-kernel/20231213093701.03fddec0@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Arun Easi <aeasi@marvell.com>
Cc: Daniel Wagner <dwagner@suse.de>
Tested-by: Dmytro Maluka <dmaluka@chromium.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The following can crash the kernel:
# cd /sys/kernel/tracing
# echo 'p:sched schedule' > kprobe_events
# exec 5>>events/kprobes/sched/enable
# > kprobe_events
# exec 5>&-
The above commands:
1. Change directory to the tracefs directory
2. Create a kprobe event (doesn't matter what one)
3. Open bash file descriptor 5 on the enable file of the kprobe event
4. Delete the kprobe event (removes the files too)
5. Close the bash file descriptor 5
The above causes a crash!
BUG: kernel NULL pointer dereference, address: 0000000000000028
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 6 PID: 877 Comm: bash Not tainted 6.5.0-rc4-test-00008-g2c6b6b1029d4-dirty #186
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:tracing_release_file_tr+0xc/0x50
What happens here is that the kprobe event creates a trace_event_file
"file" descriptor that represents the file in tracefs to the event. It
maintains state of the event (is it enabled for the given instance?).
Opening the "enable" file gets a reference to the event "file" descriptor
via the open file descriptor. When the kprobe event is deleted, the file is
also deleted from the tracefs system which also frees the event "file"
descriptor.
But as the tracefs file is still opened by user space, it will not be
totally removed until the final dput() is called on it. But this is not
true with the event "file" descriptor that is already freed. If the user
does a write to or simply closes the file descriptor it will reference the
event "file" descriptor that was just freed, causing a use-after-free bug.
To solve this, add a ref count to the event "file" descriptor as well as a
new flag called "FREED". The "file" will not be freed until the last
reference is released. But the FREE flag will be set when the event is
removed to prevent any more modifications to that event from happening,
even if there's still a reference to the event "file" descriptor.
Link: https://lore.kernel.org/linux-trace-kernel/20231031000031.1e705592@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20231031122453.7a48b923@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: f5ca233e2e ("tracing: Increase trace array ref count on enable and filter files")
Reported-by: Beau Belgrave <beaub@linux.microsoft.com>
Tested-by: Beau Belgrave <beaub@linux.microsoft.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The eventfs_create_dir() function returns error pointers, it never returns
NULL. Update the check to reflect that.
Link: https://lore.kernel.org/linux-trace-kernel/ff641474-84e2-46a7-9d7a-62b251a1050c@moroto.mountain
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 5790b1fb3d ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The system_callback() function in trace_events.c is only used within that
file. The "static" annotation was missed.
Fixes: 5790b1fb3d ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310051743.y9EobbUr-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The update to removing the eventfs_file changed the way the events top
level directory was handled. Instead of returning a dentry, it now returns
the eventfs_inode. In this changed, the removing of the events top level
directory is not much different than removing any of the other
directories. Because of this, the removal just called eventfs_remove_dir()
instead of eventfs_remove_events_dir().
Although eventfs_remove_dir() does the clean up, it misses out on the
dget() of the ei->dentry done in eventfs_create_events_dir(). It makes
more sense to match eventfs_create_events_dir() with a specific function
eventfs_remove_events_dir() and this specific function can then perform
the dput() to the dentry that had the dget() when it was created.
Fixes: 5790b1fb3d ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310051743.y9EobbUr-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Instead of having a descriptor for every file represented in the eventfs
directory, only have the directory itself represented. Change the API to
send in a list of entries that represent all the files in the directory
(but not other directories). The entry list contains a name and a callback
function that will be used to create the files when they are accessed.
struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry *parent,
const struct eventfs_entry *entries,
int size, void *data);
is used for the top level eventfs directory, and returns an eventfs_inode
that will be used by:
struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode *parent,
const struct eventfs_entry *entries,
int size, void *data);
where both of the above take an array of struct eventfs_entry entries for
every file that is in the directory.
The entries are defined by:
typedef int (*eventfs_callback)(const char *name, umode_t *mode, void **data,
const struct file_operations **fops);
struct eventfs_entry {
const char *name;
eventfs_callback callback;
};
Where the name is the name of the file and the callback gets called when
the file is being created. The callback passes in the name (in case the
same callback is used for multiple files), a pointer to the mode, data and
fops. The data will be pointing to the data that was passed in
eventfs_create_dir() or eventfs_create_events_dir() but may be overridden
to point to something else, as it will be used to point to the
inode->i_private that is created. The information passed back from the
callback is used to create the dentry/inode.
If the callback fills the data and the file should be created, it must
return a positive number. On zero or negative, the file is ignored.
This logic may also be used as a prototype to convert entire pseudo file
systems into just-in-time allocation.
The "show_events_dentry" file has been updated to show the directories,
and any files they have.
With just the eventfs_file allocations:
Before after deltas for meminfo (in kB):
MemFree: -14360
MemAvailable: -14260
Buffers: 40
Cached: 24
Active: 44
Inactive: 48
Inactive(anon): 28
Active(file): 44
Inactive(file): 20
Dirty: -4
AnonPages: 28
Mapped: 4
KReclaimable: 132
Slab: 1604
SReclaimable: 132
SUnreclaim: 1472
Committed_AS: 12
Before after deltas for slabinfo:
<slab>: <objects> [ * <size> = <total>]
ext4_inode_cache 27 [* 1184 = 31968 ]
extent_status 102 [* 40 = 4080 ]
tracefs_inode_cache 144 [* 656 = 94464 ]
buffer_head 39 [* 104 = 4056 ]
shmem_inode_cache 49 [* 800 = 39200 ]
filp -53 [* 256 = -13568 ]
dentry 251 [* 192 = 48192 ]
lsm_file_cache 277 [* 32 = 8864 ]
vm_area_struct -14 [* 184 = -2576 ]
trace_event_file 1748 [* 88 = 153824 ]
kmalloc-1k 35 [* 1024 = 35840 ]
kmalloc-256 49 [* 256 = 12544 ]
kmalloc-192 -28 [* 192 = -5376 ]
kmalloc-128 -30 [* 128 = -3840 ]
kmalloc-96 10581 [* 96 = 1015776 ]
kmalloc-64 3056 [* 64 = 195584 ]
kmalloc-32 1291 [* 32 = 41312 ]
kmalloc-16 2310 [* 16 = 36960 ]
kmalloc-8 9216 [* 8 = 73728 ]
Free memory dropped by 14,360 kB
Available memory dropped by 14,260 kB
Total slab additions in size: 1,771,032 bytes
With this change:
Before after deltas for meminfo (in kB):
MemFree: -12084
MemAvailable: -11976
Buffers: 32
Cached: 32
Active: 72
Inactive: 168
Inactive(anon): 176
Active(file): 72
Inactive(file): -8
Dirty: 24
AnonPages: 196
Mapped: 8
KReclaimable: 148
Slab: 836
SReclaimable: 148
SUnreclaim: 688
Committed_AS: 324
Before after deltas for slabinfo:
<slab>: <objects> [ * <size> = <total>]
tracefs_inode_cache 144 [* 656 = 94464 ]
shmem_inode_cache -23 [* 800 = -18400 ]
filp -92 [* 256 = -23552 ]
dentry 179 [* 192 = 34368 ]
lsm_file_cache -3 [* 32 = -96 ]
vm_area_struct -13 [* 184 = -2392 ]
trace_event_file 1748 [* 88 = 153824 ]
kmalloc-1k -49 [* 1024 = -50176 ]
kmalloc-256 -27 [* 256 = -6912 ]
kmalloc-128 1864 [* 128 = 238592 ]
kmalloc-64 4685 [* 64 = 299840 ]
kmalloc-32 -72 [* 32 = -2304 ]
kmalloc-16 256 [* 16 = 4096 ]
total = 721352
Free memory dropped by 12,084 kB
Available memory dropped by 11,976 kB
Total slab additions in size: 721,352 bytes
That's over 2 MB in savings per instance for free and available memory,
and over 1 MB in savings per instance of slab memory.
Link: https://lore.kernel.org/linux-trace-kernel/20231003184059.4924468e@gandalf.local.home
Link: https://lore.kernel.org/linux-trace-kernel/20231004165007.43d79161@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The ring buffer of global_trace is set to the minimum size in
order to save memory on boot up and then it will be expand when
some trace feature enabled.
However currently operations under an instance can also cause
global_trace ring buffer being expanded, and the expanded memory
would be wasted if global_trace then not being used.
See following case, we enable 'sched_switch' event in instance 'A', then
ring buffer of global_trace is unexpectedly expanded to be 1410KB, also
the '(expanded: 1408)' from 'buffer_size_kb' of instance is confusing.
# cd /sys/kernel/tracing
# mkdir instances/A
# cat buffer_size_kb
7 (expanded: 1408)
# cat instances/A/buffer_size_kb
1410 (expanded: 1408)
# echo sched:sched_switch > instances/A/set_event
# cat buffer_size_kb
1410
# cat instances/A/buffer_size_kb
1410
To fix it, we can:
- Make 'ring_buffer_expanded' as a member of 'struct trace_array';
- Make 'ring_buffer_expanded' of instance is defaultly true,
global_trace is defaultly false;
- In order not to expose 'global_trace' outside of file
'kernel/trace/trace.c', introduce trace_set_ring_buffer_expanded()
to set 'ring_buffer_expanded' as 'true';
- Pass the expected trace_array to tracing_update_buffers().
Link: https://lore.kernel.org/linux-trace-kernel/20230906091837.3998020-1-zhengyejian1@huawei.com
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When kernel is compiled without preemption, the eval_map_work_func()
(which calls trace_event_eval_update()) will not be preempted up to its
complete execution. This can actually cause a problem since if another
CPU call stop_machine(), the call will have to wait for the
eval_map_work_func() function to finish executing in the workqueue
before being able to be scheduled. This problem was observe on a SMP
system at boot time, when the CPU calling the initcalls executed
clocksource_done_booting() which in the end calls stop_machine(). We
observed a 1 second delay because one CPU was executing
eval_map_work_func() and was not preempted by the stop_machine() task.
Adding a call to cond_resched() in trace_event_eval_update() allows
other tasks to be executed and thus continue working asynchronously
like before without blocking any pending task at boot time.
Link: https://lore.kernel.org/linux-trace-kernel/20230929191637.416931-1-cleger@rivosinc.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Now that eventfs structure is used to create the events directory via the
eventfs dynamically allocate code, the "dir" field of the trace_event_file
structure is no longer used. Remove it.
Link: https://lkml.kernel.org/r/20230908022001.580400115@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When the trace event enable and filter files are opened, increment the
trace array ref counter, otherwise they can be accessed when the trace
array is being deleted. The ref counter keeps the trace array from being
deleted while those files are opened.
Link: https://lkml.kernel.org/r/20230907024803.456187066@goodmis.org
Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 8530dec63e ("tracing: Add tracing_check_open_get_tr()")
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Up until now, /sys/kernel/tracing/events was no different than any other
part of tracefs. The files and directories within the events directory was
created when the tracefs was mounted, and also created for the instances in
/sys/kernel/tracing/instances/<instance>/events. Most of these files and
directories will never be referenced. Since there are thousands of these
files and directories they spend their time wasting precious memory
resources.
Move the "events" directory to the new eventfs. The eventfs will take the
meta data of the events that they represent and store that. When the files
in the events directory are referenced, the dentry and inodes to represent
them are then created. When the files are no longer referenced, they are
freed. This saves the precious memory resources that were wasted on these
seldom referenced dentries and inodes.
Running the following:
~# cat /proc/meminfo /proc/slabinfo > before.out
~# mkdir /sys/kernel/tracing/instances/foo
~# cat /proc/meminfo /proc/slabinfo > after.out
to test the changes produces the following deltas:
Before this change:
Before after deltas for meminfo:
MemFree: -32260
MemAvailable: -21496
KReclaimable: 21528
Slab: 22440
SReclaimable: 21528
SUnreclaim: 912
VmallocUsed: 16
Before after deltas for slabinfo:
<slab>: <objects> [ * <size> = <total>]
tracefs_inode_cache: 14472 [* 1184 = 17134848]
buffer_head: 24 [* 168 = 4032]
hmem_inode_cache: 28 [* 1480 = 41440]
dentry: 14450 [* 312 = 4508400]
lsm_inode_cache: 14453 [* 32 = 462496]
vma_lock: 11 [* 152 = 1672]
vm_area_struct: 2 [* 184 = 368]
trace_event_file: 1748 [* 88 = 153824]
kmalloc-256: 1072 [* 256 = 274432]
kmalloc-64: 2842 [* 64 = 181888]
Total slab additions in size: 22,763,400 bytes
With this change:
Before after deltas for meminfo:
MemFree: -12600
MemAvailable: -12580
Cached: 24
Active: 12
Inactive: 68
Inactive(anon): 48
Active(file): 12
Inactive(file): 20
Dirty: -4
AnonPages: 68
KReclaimable: 12
Slab: 1856
SReclaimable: 12
SUnreclaim: 1844
KernelStack: 16
PageTables: 36
VmallocUsed: 16
Before after deltas for slabinfo:
<slab>: <objects> [ * <size> = <total>]
tracefs_inode_cache: 108 [* 1184 = 127872]
buffer_head: 24 [* 168 = 4032]
hmem_inode_cache: 18 [* 1480 = 26640]
dentry: 127 [* 312 = 39624]
lsm_inode_cache: 152 [* 32 = 4864]
vma_lock: 67 [* 152 = 10184]
vm_area_struct: -12 [* 184 = -2208]
trace_event_file: 1764 [* 96 = 169344]
kmalloc-96: 14322 [* 96 = 1374912]
kmalloc-64: 2814 [* 64 = 180096]
kmalloc-32: 1103 [* 32 = 35296]
kmalloc-16: 2308 [* 16 = 36928]
kmalloc-8: 12800 [* 8 = 102400]
Total slab additions in size: 2,109,984 bytes
Which is a savings of 20,653,416 bytes (20 MB) per tracing instance.
Link: https://lkml.kernel.org/r/1690568452-46553-10-git-send-email-akaher@vmware.com
Signed-off-by: Ajay Kaher <akaher@vmware.com>
Co-developed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Ching-lin Yu <chinglinyu@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The creation of the trace event directory requires that a TRACE_SYSTEM is
defined that the trace event directory is added within the system it was
defined in.
The code handled the case where a TRACE_SYSTEM was not added, and would
then add the event at the events directory. But nothing should be doing
this. This code also prevents the implementation of creating dynamic
dentrys for the eventfs system.
As this path has never been hit on correct code, remove it. If it does get
hit, issues a WARN_ON_ONCE() and return ENODEV.
Link: https://lkml.kernel.org/r/1690568452-46553-2-git-send-email-akaher@vmware.com
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Warning happened in trace_buffered_event_disable() at
WARN_ON_ONCE(!trace_buffered_event_ref)
Call Trace:
? __warn+0xa5/0x1b0
? trace_buffered_event_disable+0x189/0x1b0
__ftrace_event_enable_disable+0x19e/0x3e0
free_probe_data+0x3b/0xa0
unregister_ftrace_function_probe_func+0x6b8/0x800
event_enable_func+0x2f0/0x3d0
ftrace_process_regex.isra.0+0x12d/0x1b0
ftrace_filter_write+0xe6/0x140
vfs_write+0x1c9/0x6f0
[...]
The cause of the warning is in __ftrace_event_enable_disable(),
trace_buffered_event_enable() was called once while
trace_buffered_event_disable() was called twice.
Reproduction script show as below, for analysis, see the comments:
```
#!/bin/bash
cd /sys/kernel/tracing/
# 1. Register a 'disable_event' command, then:
# 1) SOFT_DISABLED_BIT was set;
# 2) trace_buffered_event_enable() was called first time;
echo 'cmdline_proc_show:disable_event:initcall:initcall_finish' > \
set_ftrace_filter
# 2. Enable the event registered, then:
# 1) SOFT_DISABLED_BIT was cleared;
# 2) trace_buffered_event_disable() was called first time;
echo 1 > events/initcall/initcall_finish/enable
# 3. Try to call into cmdline_proc_show(), then SOFT_DISABLED_BIT was
# set again!!!
cat /proc/cmdline
# 4. Unregister the 'disable_event' command, then:
# 1) SOFT_DISABLED_BIT was cleared again;
# 2) trace_buffered_event_disable() was called second time!!!
echo '!cmdline_proc_show:disable_event:initcall:initcall_finish' > \
set_ftrace_filter
```
To fix it, IIUC, we can change to call trace_buffered_event_enable() at
fist time soft-mode enabled, and call trace_buffered_event_disable() at
last time soft-mode disabled.
Link: https://lore.kernel.org/linux-trace-kernel/20230726095804.920457-1-zhengyejian1@huawei.com
Cc: <mhiramat@kernel.org>
Fixes: 0fc1b09ff1 ("tracing: Use temp buffer when filtering events")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
- Fix KMSAN vs FORTIFY in strlcpy/strlcat (Alexander Potapenko)
- Convert strreplace() to return string start (Andy Shevchenko)
- Flexible array conversions (Arnd Bergmann, Wyes Karny, Kees Cook)
- Add missing function prototypes seen with W=1 (Arnd Bergmann)
- Fix strscpy() kerndoc typo (Arne Welzel)
- Replace strlcpy() with strscpy() across many subsystems which were
either Acked by respective maintainers or were trivial changes that
went ignored for multiple weeks (Azeem Shaikh)
- Remove unneeded cc-option test for UBSAN_TRAP (Nick Desaulniers)
- Add KUnit tests for strcat()-family
- Enable KUnit tests of FORTIFY wrappers under UML
- Add more complete FORTIFY protections for strlcat()
- Add missed disabling of FORTIFY for all arch purgatories.
- Enable -fstrict-flex-arrays=3 globally
- Tightening UBSAN_BOUNDS when using GCC
- Improve checkpatch to check for strcpy, strncpy, and fake flex arrays
- Improve use of const variables in FORTIFY
- Add requested struct_size_t() helper for types not pointers
- Add __counted_by macro for annotating flexible array size members
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Merge tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook:
"There are three areas of note:
A bunch of strlcpy()->strscpy() conversions ended up living in my tree
since they were either Acked by maintainers for me to carry, or got
ignored for multiple weeks (and were trivial changes).
The compiler option '-fstrict-flex-arrays=3' has been enabled
globally, and has been in -next for the entire devel cycle. This
changes compiler diagnostics (though mainly just -Warray-bounds which
is disabled) and potential UBSAN_BOUNDS and FORTIFY _warning_
coverage. In other words, there are no new restrictions, just
potentially new warnings. Any new FORTIFY warnings we've seen have
been fixed (usually in their respective subsystem trees). For more
details, see commit df8fc4e934.
The under-development compiler attribute __counted_by has been added
so that we can start annotating flexible array members with their
associated structure member that tracks the count of flexible array
elements at run-time. It is possible (likely?) that the exact syntax
of the attribute will change before it is finalized, but GCC and Clang
are working together to sort it out. Any changes can be made to the
macro while we continue to add annotations.
As an example of that last case, I have a treewide commit waiting with
such annotations found via Coccinelle:
https://git.kernel.org/linus/adc5b3cb48a049563dc673f348eab7b6beba8a9b
Also see commit dd06e72e68 for more details.
Summary:
- Fix KMSAN vs FORTIFY in strlcpy/strlcat (Alexander Potapenko)
- Convert strreplace() to return string start (Andy Shevchenko)
- Flexible array conversions (Arnd Bergmann, Wyes Karny, Kees Cook)
- Add missing function prototypes seen with W=1 (Arnd Bergmann)
- Fix strscpy() kerndoc typo (Arne Welzel)
- Replace strlcpy() with strscpy() across many subsystems which were
either Acked by respective maintainers or were trivial changes that
went ignored for multiple weeks (Azeem Shaikh)
- Remove unneeded cc-option test for UBSAN_TRAP (Nick Desaulniers)
- Add KUnit tests for strcat()-family
- Enable KUnit tests of FORTIFY wrappers under UML
- Add more complete FORTIFY protections for strlcat()
- Add missed disabling of FORTIFY for all arch purgatories.
- Enable -fstrict-flex-arrays=3 globally
- Tightening UBSAN_BOUNDS when using GCC
- Improve checkpatch to check for strcpy, strncpy, and fake flex
arrays
- Improve use of const variables in FORTIFY
- Add requested struct_size_t() helper for types not pointers
- Add __counted_by macro for annotating flexible array size members"
* tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (54 commits)
netfilter: ipset: Replace strlcpy with strscpy
uml: Replace strlcpy with strscpy
um: Use HOST_DIR for mrproper
kallsyms: Replace all non-returning strlcpy with strscpy
sh: Replace all non-returning strlcpy with strscpy
of/flattree: Replace all non-returning strlcpy with strscpy
sparc64: Replace all non-returning strlcpy with strscpy
Hexagon: Replace all non-returning strlcpy with strscpy
kobject: Use return value of strreplace()
lib/string_helpers: Change returned value of the strreplace()
jbd2: Avoid printing outside the boundary of the buffer
checkpatch: Check for 0-length and 1-element arrays
riscv/purgatory: Do not use fortified string functions
s390/purgatory: Do not use fortified string functions
x86/purgatory: Do not use fortified string functions
acpi: Replace struct acpi_table_slit 1-element array with flex-array
clocksource: Replace all non-returning strlcpy with strscpy
string: use __builtin_memcpy() in strlcpy/strlcat
staging: most: Replace all non-returning strlcpy with strscpy
drm/i2c: tda998x: Replace all non-returning strlcpy with strscpy
...
strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement with strlcpy is safe.
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89
Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230516143956.1367827-1-azeemshaikh38@gmail.com
The histogram and synthetic events can use a pseudo event called
"stacktrace" that will create a stacktrace at the time of the event and
use it just like it was a normal field. We have other pseudo events such
as "common_cpu" and "common_timestamp". To stay consistent with that,
convert "stacktrace" to "common_stacktrace". As this was used in older
kernels, to keep backward compatibility, this will act just like
"common_cpu" did with "cpu". That is, "cpu" will be the same as
"common_cpu" unless the event has a "cpu" field. In which case, the
event's field is used. The same is true with "stacktrace".
Also update the documentation to reflect this change.
Link: https://lore.kernel.org/linux-trace-kernel/20230523230913.6860e28d@rorschach.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
- Add function names as a way to filter function addresses
- Add sample module to test ftrace ops and dynamic trampolines
- Allow stack traces to be passed from beginning event to end event for
synthetic events. This will allow seeing the stack trace of when a task is
scheduled out and recorded when it gets scheduled back in.
- Add trace event helper __get_buf() to use as a temporary buffer when printing
out trace event output.
- Add kernel command line to create trace instances on boot up.
- Add enabling of events to instances created at boot up.
- Add trace_array_puts() to write into instances.
- Allow boot instances to take a snapshot at the end of boot up.
- Allow live patch modules to include trace events
- Minor fixes and clean ups
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Merge tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:
- Add function names as a way to filter function addresses
- Add sample module to test ftrace ops and dynamic trampolines
- Allow stack traces to be passed from beginning event to end event for
synthetic events. This will allow seeing the stack trace of when a
task is scheduled out and recorded when it gets scheduled back in.
- Add trace event helper __get_buf() to use as a temporary buffer when
printing out trace event output.
- Add kernel command line to create trace instances on boot up.
- Add enabling of events to instances created at boot up.
- Add trace_array_puts() to write into instances.
- Allow boot instances to take a snapshot at the end of boot up.
- Allow live patch modules to include trace events
- Minor fixes and clean ups
* tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (31 commits)
tracing: Remove unnecessary NULL assignment
tracepoint: Allow livepatch module add trace event
tracing: Always use canonical ftrace path
tracing/histogram: Fix stacktrace histogram Documententation
tracing/histogram: Fix stacktrace key
tracing/histogram: Fix a few problems with stacktrace variable printing
tracing: Add BUILD_BUG() to make sure stacktrace fits in strings
tracing/histogram: Don't use strlen to find length of stacktrace variables
tracing: Allow boot instances to have snapshot buffers
tracing: Add trace_array_puts() to write into instance
tracing: Add enabling of events to boot instances
tracing: Add creation of instances at boot command line
tracing: Fix trace_event_raw_event_synth() if else statement
samples: ftrace: Make some global variables static
ftrace: sample: avoid open-coded 64-bit division
samples: ftrace: Include the nospec-branch.h only for x86
tracing: Acquire buffer from temparary trace sequence
tracing/histogram: Wrap remaining shell snippets in code blocks
tracing/osnoise: No need for schedule_hrtimeout range
bpf/tracing: Use stage6 of tracing to not duplicate macros
...
trace_define_field_ext() is not used outside of trace_events.c, it should
be static.
Link: https://lore.kernel.org/oe-kbuild-all/202302130750.679RaRog-lkp@intel.com/
Fixes: b6c7abd1c2 ("tracing: Fix TASK_COMM_LEN in trace event format file")
Reported-by: Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
After commit 3087c61ed2 ("tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN"),
the content of the format file under
/sys/kernel/tracing/events/task/task_newtask was changed from
field:char comm[16]; offset:12; size:16; signed:0;
to
field:char comm[TASK_COMM_LEN]; offset:12; size:16; signed:0;
John reported that this change breaks older versions of perfetto.
Then Mathieu pointed out that this behavioral change was caused by the
use of __stringify(_len), which happens to work on macros, but not on enum
labels. And he also gave the suggestion on how to fix it:
:One possible solution to make this more robust would be to extend
:struct trace_event_fields with one more field that indicates the length
:of an array as an actual integer, without storing it in its stringified
:form in the type, and do the formatting in f_show where it belongs.
The result as follows after this change,
$ cat /sys/kernel/tracing/events/task/task_newtask/format
field:char comm[16]; offset:12; size:16; signed:0;
Link: https://lore.kernel.org/lkml/Y+QaZtz55LIirsUO@google.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230210155921.4610-1-laoar.shao@gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230212151303.12353-1-laoar.shao@gmail.com
Cc: stable@vger.kernel.org
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Kajetan Puchalski <kajetan.puchalski@arm.com>
CC: Qais Yousef <qyousef@layalina.io>
Fixes: 3087c61ed2 ("tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN")
Reported-by: John Stultz <jstultz@google.com>
Debugged-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Add the format of:
trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall
That will create the "foo" instance and enable the sched_switch event
(here were the "sched" system is explicitly specified), the
irq_handler_entry event, and all events under the system initcall.
Link: https://lkml.kernel.org/r/20230207173026.386114535@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
There's been several times where an event records a function address in
its field and I needed to filter on that address for a specific function
name. It required looking up the function in kallsyms, finding its size,
and doing a compare of "field >= function_start && field < function_end".
But this would change from boot to boot and is unreliable in scripts.
Also, it is useful to have this at boot up, where the addresses will not
be known. For example, on the boot command line:
trace_trigger="initcall_finish.traceoff if func.function == acpi_init"
To implement this, add a ".function" prefix, that will check that the
field is of size long, and the only operations allowed (so far) are "=="
and "!=".
Link: https://lkml.kernel.org/r/20221219183213.916833763@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The trace_trigger command line option introduced by
commit a01fdc897f ("tracing: Add trace_trigger kernel command line option")
doesn't need to depend on the CONFIG_HIST_TRIGGERS kernel config option.
This code doesn't depend on the histogram code, and the run-time
selection of triggers is usable without CONFIG_HIST_TRIGGERS.
Link: https://lore.kernel.org/linux-trace-kernel/20221209003310.1737039-1-zwisler@google.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Fixes: a01fdc897f ("tracing: Add trace_trigger kernel command line option")
Signed-off-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Allow triggers to be enabled at kernel boot up. For example:
trace_trigger="sched_switch.stacktrace if prev_state == 2"
The above will enable the stacktrace trigger on top of the sched_switch
event and only trigger if its prev_state is 2 (TASK_UNINTERRUPTIBLE). Then
at boot up, a stacktrace will trigger and be recorded in the tracing ring
buffer every time the sched_switch happens where the previous state is
TASK_INTERRUPTIBLE.
Another useful trigger would be "traceoff" which can stop tracing on an
event if a field of the event matches a certain value defined by the
filter ("if" statement).
Link: https://lore.kernel.org/linux-trace-kernel/20221020210056.0d8d0a5b@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
After 65536 dynamic events have been added and removed, the "type" field
of the event then uses the first type number that is available (not
currently used by other events). A type number is the identifier of the
binary blobs in the tracing ring buffer (known as events) to map them to
logic that can parse the binary blob.
The issue is that if a dynamic event (like a kprobe event) is traced and
is in the ring buffer, and then that event is removed (because it is
dynamic, which means it can be created and destroyed), if another dynamic
event is created that has the same number that new event's logic on
parsing the binary blob will be used.
To show how this can be an issue, the following can crash the kernel:
# cd /sys/kernel/tracing
# for i in `seq 65536`; do
echo 'p:kprobes/foo do_sys_openat2 $arg1:u32' > kprobe_events
# done
For every iteration of the above, the writing to the kprobe_events will
remove the old event and create a new one (with the same format) and
increase the type number to the next available on until the type number
reaches over 65535 which is the max number for the 16 bit type. After it
reaches that number, the logic to allocate a new number simply looks for
the next available number. When an dynamic event is removed, that number
is then available to be reused by the next dynamic event created. That is,
once the above reaches the max number, the number assigned to the event in
that loop will remain the same.
Now that means deleting one dynamic event and created another will reuse
the previous events type number. This is where bad things can happen.
After the above loop finishes, the kprobes/foo event which reads the
do_sys_openat2 function call's first parameter as an integer.
# echo 1 > kprobes/foo/enable
# cat /etc/passwd > /dev/null
# cat trace
cat-2211 [005] .... 2007.849603: foo: (do_sys_openat2+0x0/0x130) arg1=4294967196
cat-2211 [005] .... 2007.849620: foo: (do_sys_openat2+0x0/0x130) arg1=4294967196
cat-2211 [005] .... 2007.849838: foo: (do_sys_openat2+0x0/0x130) arg1=4294967196
cat-2211 [005] .... 2007.849880: foo: (do_sys_openat2+0x0/0x130) arg1=4294967196
# echo 0 > kprobes/foo/enable
Now if we delete the kprobe and create a new one that reads a string:
# echo 'p:kprobes/foo do_sys_openat2 +0($arg2):string' > kprobe_events
And now we can the trace:
# cat trace
sendmail-1942 [002] ..... 530.136320: foo: (do_sys_openat2+0x0/0x240) arg1= cat-2046 [004] ..... 530.930817: foo: (do_sys_openat2+0x0/0x240) arg1="������������������������������������������������������������������������������������������������"
cat-2046 [004] ..... 530.930961: foo: (do_sys_openat2+0x0/0x240) arg1="������������������������������������������������������������������������������������������������"
cat-2046 [004] ..... 530.934278: foo: (do_sys_openat2+0x0/0x240) arg1="������������������������������������������������������������������������������������������������"
cat-2046 [004] ..... 530.934563: foo: (do_sys_openat2+0x0/0x240) arg1="������������������������������������������������������������������������������������������������"
bash-1515 [007] ..... 534.299093: foo: (do_sys_openat2+0x0/0x240) arg1="kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk���������@��4Z����;Y�����U
And dmesg has:
==================================================================
BUG: KASAN: use-after-free in string+0xd4/0x1c0
Read of size 1 at addr ffff88805fdbbfa0 by task cat/2049
CPU: 0 PID: 2049 Comm: cat Not tainted 6.1.0-rc6-test+ #641
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016
Call Trace:
<TASK>
dump_stack_lvl+0x5b/0x77
print_report+0x17f/0x47b
kasan_report+0xad/0x130
string+0xd4/0x1c0
vsnprintf+0x500/0x840
seq_buf_vprintf+0x62/0xc0
trace_seq_printf+0x10e/0x1e0
print_type_string+0x90/0xa0
print_kprobe_event+0x16b/0x290
print_trace_line+0x451/0x8e0
s_show+0x72/0x1f0
seq_read_iter+0x58e/0x750
seq_read+0x115/0x160
vfs_read+0x11d/0x460
ksys_read+0xa9/0x130
do_syscall_64+0x3a/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fc2e972ade2
Code: c0 e9 b2 fe ff ff 50 48 8d 3d b2 3f 0a 00 e8 05 f0 01 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24
RSP: 002b:00007ffc64e687c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007fc2e972ade2
RDX: 0000000000020000 RSI: 00007fc2e980d000 RDI: 0000000000000003
RBP: 00007fc2e980d000 R08: 00007fc2e980c010 R09: 0000000000000000
R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000020f00
R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000
</TASK>
The buggy address belongs to the physical page:
page:ffffea00017f6ec0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5fdbb
flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff)
raw: 000fffffc0000000 0000000000000000 ffffea00017f6ec8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88805fdbbe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88805fdbbf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805fdbbf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88805fdbc000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88805fdbc080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
This was found when Zheng Yejian sent a patch to convert the event type
number assignment to use IDA, which gives the next available number, and
this bug showed up in the fuzz testing by Yujie Liu and the kernel test
robot. But after further analysis, I found that this behavior is the same
as when the event type numbers go past the 16bit max (and the above shows
that).
As modules have a similar issue, but is dealt with by setting a
"WAS_ENABLED" flag when a module event is enabled, and when the module is
freed, if any of its events were enabled, the ring buffer that holds that
event is also cleared, to prevent reading stale events. The same can be
done for dynamic events.
If any dynamic event that is being removed was enabled, then make sure the
buffers they were enabled in are now cleared.
Link: https://lkml.kernel.org/r/20221123171434.545706e3@gandalf.local.home
Link: https://lore.kernel.org/all/20221110020319.1259291-1-zhengyejian1@huawei.com/
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Depends-on: e18eb8783e ("tracing: Add tracing_reset_all_online_cpus_unlocked() function")
Depends-on: 5448d44c38 ("tracing: Add unified dynamic event framework")
Depends-on: 6212dd2968 ("tracing/kprobes: Use dyn_event framework for kprobe events")
Depends-on: 065e63f951 ("tracing: Only have rmmod clear buffers that its events were active in")
Depends-on: 575380da8b ("tracing: Only clear trace buffer on module unload if event was traced")
Fixes: 77b44d1b7c ("tracing/kprobes: Rename Kprobe-tracer to kprobe-event")
Reported-by: Zheng Yejian <zhengyejian1@huawei.com>
Reported-by: Yujie Liu <yujie.liu@intel.com>
Reported-by: kernel test robot <yujie.liu@intel.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Currently the tracing_reset_all_online_cpus() requires the
trace_types_lock held. But only one caller of this function actually has
that lock held before calling it, and the other just takes the lock so
that it can call it. More users of this function is needed where the lock
is not held.
Add a tracing_reset_all_online_cpus_unlocked() function for the one use
case that calls it without being held, and also add a lockdep_assert to
make sure it is held when called.
Then have tracing_reset_all_online_cpus() take the lock internally, such
that callers do not need to worry about taking it.
Link: https://lkml.kernel.org/r/20221123192741.658273220@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Make filtering consistent with histograms. As "cpu" can be a field of an
event, allow for "common_cpu" to keep it from being confused with the
"cpu" field of the event.
Link: https://lkml.kernel.org/r/20220820134401.513062765@goodmis.org
Link: https://lore.kernel.org/all/20220820220920.e42fa32b70505b1904f0a0ad@kernel.org/
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Fixes: 1e3bac71c5 ("tracing/histogram: Rename "cpu" to "common_cpu"")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
- The majority of the changes are for fixes and clean ups.
Noticeable changes:
- Rework trace event triggers code to be easier to interact with.
- Support for embedding bootconfig with the kernel (as suppose to having it
embedded in initram). This is useful for embedded boards without initram
disks.
- Speed up boot by parallelizing the creation of tracefs files.
- Allow absolute ring buffer timestamps handle timestamps that use more than
59 bits.
- Added new tracing clock "TAI" (International Atomic Time)
- Have weak functions show up in available_filter_function list as:
__ftrace_invalid_address___<invalid-offset>
instead of using the name of the function before it.
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Merge tag 'trace-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The majority of the changes are for fixes and clean ups.
Notable changes:
- Rework trace event triggers code to be easier to interact with.
- Support for embedding bootconfig with the kernel (as suppose to
having it embedded in initram). This is useful for embedded boards
without initram disks.
- Speed up boot by parallelizing the creation of tracefs files.
- Allow absolute ring buffer timestamps handle timestamps that use
more than 59 bits.
- Added new tracing clock "TAI" (International Atomic Time)
- Have weak functions show up in available_filter_function list as:
__ftrace_invalid_address___<invalid-offset> instead of using the
name of the function before it"
* tag 'trace-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (52 commits)
ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function
tracing: Fix comments for event_trigger_separate_filter()
x86/traceponit: Fix comment about irq vector tracepoints
x86,tracing: Remove unused headers
ftrace: Clean up hash direct_functions on register failures
tracing: Fix comments of create_filter()
tracing: Disable kcov on trace_preemptirq.c
tracing: Initialize integer variable to prevent garbage return value
ftrace: Fix typo in comment
ftrace: Remove return value of ftrace_arch_modify_*()
tracing: Cleanup code by removing init "char *name"
tracing: Change "char *" string form to "char []"
tracing/timerlat: Do not wakeup the thread if the trace stops at the IRQ
tracing/timerlat: Print stacktrace in the IRQ handler if needed
tracing/timerlat: Notify IRQ new max latency only if stop tracing is set
kprobes: Fix build errors with CONFIG_KRETPROBES=n
tracing: Fix return value of trace_pid_write()
tracing: Fix potential double free in create_var_ref()
tracing: Use strim() to remove whitespace instead of doing it manually
ftrace: Deal with error return code of the ftrace_process_locs() function
...
Creating tracefs entries with tracefs_create_file() followed by pr_warn()
is tedious and repetitive, we can use trace_create_file() to simplify
this process and make the code more readable.
Link: https://lkml.kernel.org/r/20220114131052.534382-1-ytcoode@gmail.com
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The print fmt check against trace events to make sure that the format does
not use pointers that may be freed from the time of the trace to the time
the event is read, gives a false positive on %pISpc when reading data that
was saved in __get_dynamic_array() when it is perfectly fine to do so, as
the data being read is on the ring buffer.
Link: https://lore.kernel.org/all/20220407144524.2a592ed6@canb.auug.org.au/
Cc: stable@vger.kernel.org
Fixes: 5013f454a3 ("tracing: Add check of trace event print fmts for dereferencing pointers")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Commit fa2c3254d7 (sched/tracing: Don't re-read p->state when emitting
sched_switch event, 2022-01-20) added a new prev_state argument to the
sched_switch tracepoint, before the prev task_struct pointer.
This reordering of arguments broke BPF programs that use the raw
tracepoint (e.g. tp_btf programs). The type of the second argument has
changed and existing programs that assume a task_struct* argument
(e.g. for bpf_task_storage access) will now fail to verify.
If we instead append the new argument to the end, all existing programs
would continue to work and can conditionally extract the prev_state
argument on supported kernel versions.
Fixes: fa2c3254d7 (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20)
Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/c8a6930dfdd58a4a5755fc01732675472979732b.camel@fb.com
When list_for_each_entry() completes the iteration over the whole list
without breaking the loop, the iterator value will be a bogus pointer
computed based on the head element.
While it is safe to use the pointer to determine if it was computed
based on the head element, either with list_entry_is_head() or
&pos->member == head, using the iterator variable after the loop should
be avoided.
In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to point to the found element [1].
Link: https://lkml.kernel.org/r/20220427170734.819891-5-jakobkoschel@gmail.com
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
- New user_events interface. User space can register an event with the kernel
describing the format of the event. Then it will receive a byte in a page
mapping that it can check against. A privileged task can then enable that
event like any other event, which will change the mapped byte to true,
telling the user space application to start writing the event to the
tracing buffer.
- Add new "ftrace_boot_snapshot" kernel command line parameter. When set,
the tracing buffer will be saved in the snapshot buffer at boot up when
the kernel hands things over to user space. This will keep the traces that
happened at boot up available even if user space boot up has tracing as
well.
- Have TRACE_EVENT_ENUM() also update trace event field type descriptions.
Thus if a static array defines its size with an enum, the user space trace
event parsers can still know how to parse that array.
- Add new TRACE_CUSTOM_EVENT() macro. This acts the same as the
TRACE_EVENT() macro, but will attach to an existing tracepoint. This will
make one tracepoint be able to trace different content and not be stuck at
only what the original TRACE_EVENT() macro exports.
- Fixes to tracing error logging.
- Better saving of cmdlines to PIDs when tracing (use the wakeup events for
mapping).
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Merge tag 'trace-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- New user_events interface. User space can register an event with the
kernel describing the format of the event. Then it will receive a
byte in a page mapping that it can check against. A privileged task
can then enable that event like any other event, which will change
the mapped byte to true, telling the user space application to start
writing the event to the tracing buffer.
- Add new "ftrace_boot_snapshot" kernel command line parameter. When
set, the tracing buffer will be saved in the snapshot buffer at boot
up when the kernel hands things over to user space. This will keep
the traces that happened at boot up available even if user space boot
up has tracing as well.
- Have TRACE_EVENT_ENUM() also update trace event field type
descriptions. Thus if a static array defines its size with an enum,
the user space trace event parsers can still know how to parse that
array.
- Add new TRACE_CUSTOM_EVENT() macro. This acts the same as the
TRACE_EVENT() macro, but will attach to an existing tracepoint. This
will make one tracepoint be able to trace different content and not
be stuck at only what the original TRACE_EVENT() macro exports.
- Fixes to tracing error logging.
- Better saving of cmdlines to PIDs when tracing (use the wakeup events
for mapping).
* tag 'trace-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits)
tracing: Have type enum modifications copy the strings
user_events: Add trace event call as root for low permission cases
tracing/user_events: Use alloc_pages instead of kzalloc() for register pages
tracing: Add snapshot at end of kernel boot up
tracing: Have TRACE_DEFINE_ENUM affect trace event types as well
tracing: Fix strncpy warning in trace_events_synth.c
user_events: Prevent dyn_event delete racing with ioctl add/delete
tracing: Add TRACE_CUSTOM_EVENT() macro
tracing: Move the defines to create TRACE_EVENTS into their own files
tracing: Add sample code for custom trace events
tracing: Allow custom events to be added to the tracefs directory
tracing: Fix last_cmd_set() string management in histogram code
user_events: Fix potential uninitialized pointer while parsing field
tracing: Fix allocation of last_cmd in last_cmd_set()
user_events: Add documentation file
user_events: Add sample code for typical usage
user_events: Add self-test for validator boundaries
user_events: Add self-test for perf_event integration
user_events: Add self-test for dynamic_events integration
user_events: Add self-test for ftrace integration
...
- Cleanups for SCHED_DEADLINE
- Tracing updates/fixes
- CPU Accounting fixes
- First wave of changes to optimize the overhead of the scheduler build,
from the fast-headers tree - including placeholder *_api.h headers for
later header split-ups.
- Preempt-dynamic using static_branch() for ARM64
- Isolation housekeeping mask rework; preperatory for further changes
- NUMA-balancing: deal with CPU-less nodes
- NUMA-balancing: tune systems that have multiple LLC cache domains per node (eg. AMD)
- Updates to RSEQ UAPI in preparation for glibc usage
- Lots of RSEQ/selftests, for same
- Add Suren as PSI co-maintainer
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2022-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- Cleanups for SCHED_DEADLINE
- Tracing updates/fixes
- CPU Accounting fixes
- First wave of changes to optimize the overhead of the scheduler
build, from the fast-headers tree - including placeholder *_api.h
headers for later header split-ups.
- Preempt-dynamic using static_branch() for ARM64
- Isolation housekeeping mask rework; preperatory for further changes
- NUMA-balancing: deal with CPU-less nodes
- NUMA-balancing: tune systems that have multiple LLC cache domains per
node (eg. AMD)
- Updates to RSEQ UAPI in preparation for glibc usage
- Lots of RSEQ/selftests, for same
- Add Suren as PSI co-maintainer
* tag 'sched-core-2022-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits)
sched/headers: ARM needs asm/paravirt_api_clock.h too
sched/numa: Fix boot crash on arm64 systems
headers/prep: Fix header to build standalone: <linux/psi.h>
sched/headers: Only include <linux/entry-common.h> when CONFIG_GENERIC_ENTRY=y
cgroup: Fix suspicious rcu_dereference_check() usage warning
sched/preempt: Tell about PREEMPT_DYNAMIC on kernel headers
sched/topology: Remove redundant variable and fix incorrect type in build_sched_domains
sched/deadline,rt: Remove unused parameter from pick_next_[rt|dl]_entity()
sched/deadline,rt: Remove unused functions for !CONFIG_SMP
sched/deadline: Use __node_2_[pdl|dle]() and rb_first_cached() consistently
sched/deadline: Merge dl_task_can_attach() and dl_cpu_busy()
sched/deadline: Move bandwidth mgmt and reclaim functions into sched class source file
sched/deadline: Remove unused def_dl_bandwidth
sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE
sched/tracing: Don't re-read p->state when emitting sched_switch event
sched/rt: Plug rt_mutex_setprio() vs push_rt_task() race
sched/cpuacct: Remove redundant RCU read lock
sched/cpuacct: Optimize away RCU read lock
sched/cpuacct: Fix charge percpu cpuusage
sched/headers: Reorganize, clean up and optimize kernel/sched/sched.h dependencies
...
When an enum is used in the visible parts of a trace event that is
exported to user space, the user space applications like perf and
trace-cmd do not have a way to know what the value of the enum is. To
solve this, at boot up (or module load) the printk formats are modified to
replace the enum with their numeric value in the string output.
Array fields of the event are defined by [<nr-elements>] in the type
portion of the format file so that the user space parsers can correctly
parse the array into the appropriate size chunks. But in some trace
events, an enum is used in defining the size of the array, which once
again breaks the parsing of user space tooling.
This was solved the same way as the print formats were, but it modified
the type strings of the trace event. This caused crashes in some
architectures because, as supposed to the print string, is a const string
value. This was not detected on x86, as it appears that const strings are
still writable (at least in boot up), but other architectures this is not
the case, and writing to a const string will cause a kernel fault.
To fix this, use kstrdup() to copy the type before modifying it. If the
trace event is for the core kernel there's no need to free it because the
string will be in use for the life of the machine being on line. For
modules, create a link list to store all the strings being allocated for
modules and when the module is removed, free them.
Link: https://lore.kernel.org/all/yt9dr1706b4i.fsf@linux.ibm.com/
Link: https://lkml.kernel.org/r/20220318153432.3984b871@gandalf.local.home
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Fixes: b3bc8547d3 ("tracing: Have TRACE_DEFINE_ENUM affect trace event types as well")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The macro TRACE_DEFINE_ENUM is used to convert enums in the kernel to
their actual value when they are exported to user space via the trace
event format file.
Currently only the enums in the "print fmt" (TP_printk in the TRACE_EVENT
macro) have the enums converted. But the enums can be used to denote array
size:
field:unsigned int fc_ineligible_rc[EXT4_FC_REASON_MAX]; offset:12; size:36; signed:0;
The EXT4_FC_REASON_MAX has no meaning to userspace but it needs to know
that information to know how to parse the array.
Have the array indexes also be parsed as well.
Link: https://lore.kernel.org/all/cover.1646922487.git.riteshh@linux.ibm.com/
Reported-by: Ritesh Harjani <riteshh@linux.ibm.com>
Tested-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Allow custom events to be added to the events directory in the tracefs
file system. For example, a module could be installed that attaches to an
event and wants to be enabled and disabled via the tracefs file system. It
would use trace_add_event_call() to add the event to the tracefs
directory, and trace_remove_event_call() to remove it.
Make both those functions EXPORT_SYMBOL_GPL().
Link: https://lkml.kernel.org/r/20220303220625.186988045@goodmis.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
As of commit
c6e7bd7afa ("sched/core: Optimize ttwu() spinning on p->on_cpu")
the following sequence becomes possible:
p->__state = TASK_INTERRUPTIBLE;
__schedule()
deactivate_task(p);
ttwu()
READ !p->on_rq
p->__state=TASK_WAKING
trace_sched_switch()
__trace_sched_switch_state()
task_state_index()
return 0;
TASK_WAKING isn't in TASK_REPORT, so the task appears as TASK_RUNNING in
the trace event.
Prevent this by pushing the value read from __schedule() down the trace
event.
Reported-by: Abhijeet Dharmapurikar <adharmap@quicinc.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20220120162520.570782-2-valentin.schneider@arm.com
A helper macro was added to make reading socket addresses easier in trace
events. It pairs %pISpc with __get_sockaddr() that reads the socket
address from the ring buffer into a human readable format.
The boot up check that makes sure that trace events do not reference
pointers to memory that can later be freed when the trace event is read,
incorrectly flagged this as a delayed reference. Update the check to
handle "__get_sockaddr" and not report an error on it.
Link: https://lore.kernel.org/all/20220125160505.068dbb52@canb.auug.org.au/
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Since the same warning message is already printed in the
trace_create_file() function, there is no need to print it again.
Link: https://lkml.kernel.org/r/20220109162232.361747-1-ytcoode@gmail.com
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When creating a new event (via a module, kprobe, eprobe, etc), the
descriptors that are created must add flags for pid filtering if an
instance has pid filtering enabled, as the flags are used at the time the
event is executed to know if pid filtering should be done or not.
The "Only trace this pid" case was added, but a cut and paste error made
that case checked twice, instead of checking the "Trace all but this pid"
case.
Link: https://lore.kernel.org/all/202111280401.qC0z99JB-lkp@intel.com/
Fixes: 6cb206508b ("tracing: Check pid filtering when creating events")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When pid filtering is activated in an instance, all of the events trace
files for that instance has the PID_FILTER flag set. This determines
whether or not pid filtering needs to be done on the event, otherwise the
event is executed as normal.
If pid filtering is enabled when an event is created (via a dynamic event
or modules), its flag is not updated to reflect the current state, and the
events are not filtered properly.
Cc: stable@vger.kernel.org
Fixes: 3fdaf80f4a ("tracing: Implement event pid filtering")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When building the files in the tracefs file system, do not by default set
any permissions for OTH (other). This will make it easier for admins who
want to define a group for accessing tracefs and not having to first
disable all the permission bits for "other" in the file system.
As tracing can leak sensitive information, it should never by default
allowing all users access. An admin can still set the permission bits for
others to have access, which may be useful for creating a honeypot and
seeing who takes advantage of it and roots the machine.
Link: https://lkml.kernel.org/r/20210818153038.864149276@goodmis.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Instead of having the logic that does trace_pid_list open coded, wrap it in
abstract functions. This will allow a rewrite of the logic that implements
the trace_pid_list without affecting the users.
Note, this causes a change in behavior. Every time a pid is written into
the set_*_pid file, it creates a new list and uses RCU to update it. If
pid_max is lowered, but there was a pid currently in the list that was
higher than pid_max, those pids will now be removed on updating the list.
The old behavior kept that from happening.
The rewrite of the pid_list logic will no longer depend on pid_max,
and will return the old behavior.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
migrate_disable() forbids task migration to another CPU. It is available
since v5.11 and has already users such as highmem or BPF. It is useful
to observe this task state in tracing which already has other states
like the preemption counter.
Instead of adding the migrate disable counter as a new entry to struct
trace_entry, which would extend the whole struct by four bytes, it is
squashed into the preempt-disable counter. The lower four bits represent
the preemption counter, the upper four bits represent the migrate
disable counter. Both counter shouldn't exceed 15 but if they do, there
is a safety net which caps the value at 15.
Add the migrate-disable counter to the trace entry so it shows up in the
trace. Due to the users mentioned above, it is already possible to
observe it:
| bash-1108 [000] ...21 73.950578: rss_stat: mm_id=2213312838 curr=0 type=MM_ANONPAGES size=8192B
| bash-1108 [000] d..31 73.951222: irq_disable: caller=flush_tlb_mm_range+0x115/0x130 parent=ptep_clear_flush+0x42/0x50
| bash-1108 [000] d..31 73.951222: tlb_flush: pages:1 reason:local mm shootdown (3)
The last value is the migrate-disable counter.
Things that popped up:
- trace_print_lat_context() does not print the migrate counter. Not sure
if it should. It is used in "verbose" mode and uses 8 digits and I'm
not sure ther is something processing the value.
- trace_define_common_fields() now defines a different variable. This
probably breaks things. No ide what to do in order to preserve the old
behaviour. Since this is used as a filter it should be split somehow
to be able to match both nibbles here.
Link: https://lkml.kernel.org/r/20210810132625.ylssabmsrkygokuv@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy: patch description.]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[ SDR: Removed change to common_preempt_count field name ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As dynamic events are not created by modules, if something is attached to
one, calling "try_module_get()" on its "mod" field, is not going to keep
the dynamic event from going away.
Since dynamic events do not need the "mod" pointer of the event structure,
make a union out of it in order to save memory (there's one structure for
each of the thousand+ events in the kernel), and have any event with the
DYNAMIC flag set to use a ref counter instead.
Link: https://lore.kernel.org/linux-trace-devel/20210813004448.51c7de69ce432d338f4d226b@kernel.org/
Link: https://lkml.kernel.org/r/20210817035027.174869074@goodmis.org
Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
