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e91c2518a5
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Petr Mladek e91c2518a5 livepatch: Initialize shadow variables safely by a custom callback 
The existing API allows to pass a sample data to initialize the shadow
data. It works well when the data are position independent. But it fails
miserably when we need to set a pointer to the shadow structure itself.

Unfortunately, we might need to initialize the pointer surprisingly
often because of struct list_head. It is even worse because the list
might be hidden in other common structures, for example, struct mutex,
struct wait_queue_head.

For example, this was needed to fix races in ALSA sequencer. It required
to add mutex into struct snd_seq_client. See commit b3defb791b
("ALSA: seq: Make ioctls race-free") and commit d15d662e89
("ALSA: seq: Fix racy pool initializations")

This patch makes the API more safe. A custom constructor function and data
are passed to klp_shadow_*alloc() functions instead of the sample data.

Note that ctor_data are no longer a template for shadow->data. It might
point to any data that might be necessary when the constructor is called.

Also note that the constructor is called under klp_shadow_lock. It is
an internal spin_lock that synchronizes alloc() vs. get() operations,
see klp_shadow_get_or_alloc(). On one hand, this adds a risk of ABBA
deadlocks. On the other hand, it allows to do some operations safely.
For example, we could add the new structure into an existing list.
This must be done only once when the structure is allocated.

Reported-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2018-04-17 13:42:48 +02:00
..
bpf Merge branch 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-01-30 18:32:21 -08:00
cgroup string: drop __must_check from strscpy() and restore strscpy() usages in cgroup 2018-01-19 08:51:36 -08:00
configs PM: Provide a config snippet for disabling PM 2017-12-04 15:14:48 +01:00
debug signal: Simplify and fix kdb_send_sig 2018-01-03 18:01:08 -06:00
events Merge branch 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-01-30 17:58:07 -08:00
gcov License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-29 16:47:21 -08:00
livepatch livepatch: Initialize shadow variables safely by a custom callback 2018-04-17 13:42:48 +02:00
locking Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-30 10:44:56 -08:00
power Merge branch 'for-4.16/block' of git://git.kernel.dk/linux-block 2018-01-29 11:51:49 -08:00
printk Merge branch 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-01-30 17:58:07 -08:00
rcu SCSI misc on 20180131 2018-01-31 11:23:28 -08:00
sched Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-30 11:55:56 -08:00
time Merge branch 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-01-30 17:58:07 -08:00
trace Merge branch 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-01-30 17:58:07 -08:00
.gitignore
acct.c kernel/acct.c: fix the acct->needcheck check in check_free_space() 2018-01-04 16:45:09 -08:00
async.c
audit_fsnotify.c
audit_tree.c Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2017-11-14 14:08:20 -08:00
audit_watch.c audit/stable-4.13 PR 20170816 2017-08-16 16:48:34 -07:00
audit.c Audit: remove unused audit_log_secctx function 2017-11-10 16:08:47 -05:00
audit.h audit/stable-4.15 PR 20171113 2017-11-15 13:28:48 -08:00
auditfilter.c audit: filter PATH records keyed on filesystem magic 2017-11-10 16:08:56 -05:00
auditsc.c audit/stable-4.15 PR 20171113 2017-11-15 13:28:48 -08:00
backtracetest.c
bounds.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
capability.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat.c sched_rr_get_interval(): move compat to native, get rid of set_fs() 2017-09-20 00:30:57 -04:00
configs.c
context_tracking.c
cpu_pm.c PM / CPU: replace raw_notifier with atomic_notifier 2017-07-31 13:09:49 +02:00
cpu.c Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 12:30:34 -08:00
crash_core.c kdump: write correct address of mem_section into vmcoreinfo 2018-01-13 10:42:48 -08:00
crash_dump.c
cred.c
delayacct.c delayacct: Account blkio completion on the correct task 2018-01-16 03:29:36 +01:00
dma.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
elfcore.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
exec_domain.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
exit.c kernel/exit.c: export abort() to modules 2018-01-04 16:45:09 -08:00
extable.c kprobes, x86/alternatives: Use text_mutex to protect smp_alt_modules 2017-11-07 12:20:09 +01:00
fork.c Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-23 11:53:04 -08:00
freezer.c
futex_compat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
futex.c futex: Fix OWNER_DEAD fixup 2018-01-24 09:58:18 +01:00
groups.c kernel: make groups_sort calling a responsibility group_info allocators 2017-12-14 16:00:49 -08:00
hung_task.c
irq_work.c irq/work: Improve the flag definitions 2018-01-08 19:43:15 +01:00
jump_label.c sched/core: Fix cpu.max vs. cpuhotplug deadlock 2018-01-24 10:03:44 +01:00
kallsyms.c kallsyms: take advantage of the new '%px' format 2017-11-29 10:30:13 -08:00
kcmp.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: fix comparison callback signature 2017-12-14 16:00:48 -08:00
kexec_core.c x86/mm, kexec: Allow kexec to be used with SME 2017-07-18 11:38:04 +02:00
kexec_file.c resource: Provide resource struct in resource walk callback 2017-11-07 15:35:57 +01:00
kexec_internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kexec.c kdump: protect vmcoreinfo data under the crash memory 2017-07-12 16:26:00 -07:00
kmod.c kmod: move #ifdef CONFIG_MODULES wrapper to Makefile 2017-09-08 18:26:51 -07:00
kprobes.c kprobes: Disable the jprobes APIs 2017-10-20 11:02:29 +02:00
ksysfs.c kexec: move vmcoreinfo out of the kernel's .bss section 2017-07-12 16:25:59 -07:00
kthread.c treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts 2017-11-21 16:35:54 -08:00
latencytop.c
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
memremap.c memremap: add scheduling point to devm_memremap_pages 2017-10-03 17:54:25 -07:00
module_signing.c
module-internal.h
module.c Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-29 19:08:02 -08:00
notifier.c
nsproxy.c
padata.c treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
panic.c kernel/panic.c: add TAINT_AUX 2017-11-17 16:10:04 -08:00
params.c kernel/params.c: improve STANDARD_PARAM_DEF readability 2017-10-03 17:54:26 -07:00
pid_namespace.c pid: remove pidhash 2017-11-17 16:10:04 -08:00
pid.c init_task out-of-lining 2018-01-29 09:08:34 -08:00
profile.c
ptrace.c ptrace: Use copy_siginfo in setsiginfo and getsiginfo 2018-01-16 12:48:30 -06:00
range.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
reboot.c kernel/reboot.c: add devm_register_reboot_notifier() 2017-11-17 16:10:04 -08:00
relay.c ipc, kernel, mm: annotate ->poll() instances 2017-11-27 16:20:05 -05:00
resource.c x86/mm, resource: Use PAGE_KERNEL protection for ioremap of memory pages 2017-11-07 15:35:58 +01:00
seccomp.c signal: Replace memset(info,...) with clear_siginfo for clarity 2018-01-22 19:07:08 -06:00
signal.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2018-01-31 13:02:18 -08:00
smp.c smp/core: Use lockdep to assert IRQs are disabled/enabled 2017-11-08 11:13:50 +01:00
smpboot.c watchdog/core, powerpc: Lock cpus across reconfiguration 2017-10-04 10:53:54 +02:00
smpboot.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
softirq.c softirq: Eliminate cond_resched_rcu_qs() in favor of cond_resched() 2017-12-04 10:28:58 -08:00
stacktrace.c
stop_machine.c
sys_ni.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sys.c fix typo in assignment of fs default overflow gid 2017-12-14 16:01:45 -06:00
sysctl_binary.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sysctl.c kernel/sysctl.c: code cleanups 2017-11-17 16:10:03 -08:00
task_work.c locking/barriers: Convert users of lockless_dereference() to READ_ONCE() 2017-12-17 13:57:15 +01:00
taskstats.c
test_kprobes.c kprobes: Disable the jprobes test code 2017-10-20 11:02:54 +02:00
torture.c torture: Save a line in stutter_wait(): while -> for 2017-12-11 09:18:30 -08:00
tracepoint.c tracepoint: Remove smp_read_barrier_depends() from comment 2017-12-04 10:52:56 -08:00
tsacct.c
ucount.c
uid16.c kernel: make groups_sort calling a responsibility group_info allocators 2017-12-14 16:00:49 -08:00
umh.c kernel/umh.c: optimize 'proc_cap_handler()' 2017-11-17 16:10:01 -08:00
up.c smp: Avoid using two cache lines for struct call_single_data 2017-08-29 15:14:38 +02:00
user_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2017-11-16 12:20:15 -08:00
user-return-notifier.c
user.c userns: use union in {g,u}idmap struct 2017-10-31 17:22:58 -05:00
utsname_sysctl.c
utsname.c
watchdog_hld.c Merge branch 'linus' into core/urgent, to pick up dependent commits 2017-11-04 08:53:04 +01:00
watchdog.c Merge branch 'linus' into sched/core, to pick up fixes 2017-11-08 10:17:15 +01:00
workqueue_internal.h Merge branch 'for-4.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2017-11-06 12:26:49 -08:00
workqueue.c Merge branch 'for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2018-01-30 14:45:39 -08:00