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linux/kernel
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Lorenzo Stoakes 985da552a9 fork: only invoke khugepaged, ksm hooks if no error 
There is no reason to invoke these hooks early against an mm that is in an
incomplete state.

The change in commit d240629148 ("fork: use __mt_dup() to duplicate
maple tree in dup_mmap()") makes this more pertinent as we may be in a
state where entries in the maple tree are not yet consistent.

Their placement early in dup_mmap() only appears to have been meaningful
for early error checking, and since functionally it'd require a very small
allocation to fail (in practice 'too small to fail') that'd only occur in
the most dire circumstances, meaning the fork would fail or be OOM'd in
any case.

Since both khugepaged and KSM tracking are there to provide optimisations
to memory performance rather than critical functionality, it doesn't
really matter all that much if, under such dire memory pressure, we fail
to register an mm with these.

As a result, we follow the example of commit d2081b2bf8 ("mm:
khugepaged: make khugepaged_enter() void function") and make ksm_fork() a
void function also.

We only expose the mm to these functions once we are done with them and
only if no error occurred in the fork operation.

Link: https://lkml.kernel.org/r/e0cb8b840c9d1d5a6e84d4f8eff5f3f2022aa10c.1729014377.git.lorenzo.stoakes@oracle.com
Fixes: d240629148 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: Jann Horn <jannh@google.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Jann Horn <jannh@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-28 21:40:39 -07:00
..
bpf bpf: Check validity of link->type in bpf_link_show_fdinfo() 2024-10-24 10:17:12 -07:00
cgroup struct fd layout change (and conversion to accessor helpers) 2024-09-23 09:35:36 -07:00
configs tinyconfig: remove unnecessary 'is not set' for choice blocks 2024-09-01 20:34:38 +09:00
debug move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
dma dma-mapping: report unlimited DMA addressing in IOMMU DMA path 2024-09-23 08:38:56 +02:00
entry treewide: context_tracking: Rename CONTEXT_* into CT_STATE_* 2024-07-29 07:33:10 +05:30
events sched/fair: Fix external p->on_rq users 2024-10-14 09:14:35 +02:00
futex fault-inject: improve build for CONFIG_FAULT_INJECTION=n 2024-09-01 20:43:33 -07:00
gcov gcov: add support for GCC 14 2024-06-15 10:43:06 -07:00
irq pci-v6.12-changes 2024-09-23 12:47:06 -07:00
kcsan kcsan: Use min() to fix Coccinelle warning 2024-08-01 16:40:44 -07:00
livepatch livepatch: Replace snprintf() with sysfs_emit() 2024-07-02 16:56:18 +02:00
locking Locking changes for v6.12: 2024-09-29 08:51:30 -07:00
module Modules changes for v6.12-rc1 2024-09-28 09:06:15 -07:00
power [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
printk drm next for 6.12-rc1 2024-09-19 10:18:15 +02:00
rcu Merge branch 'linus' into sched/urgent, to resolve conflict 2024-10-17 09:58:07 +02:00
sched Merge branch 'linus' into sched/urgent, to resolve conflict 2024-10-17 09:58:07 +02:00
time Including fixes from netfiler, xfrm and bluetooth. 2024-10-24 16:43:50 -07:00
trace Fixes for function graph: 2024-10-27 08:56:22 -10:00
.gitignore
acct.c kernel misc: Remove the now superfluous sentinel elements from ctl_table array 2024-04-24 09:43:53 +02:00
async.c async: Use a dedicated unbound workqueue with raised min_active 2024-02-09 11:13:59 -10:00
audit_fsnotify.c
audit_tree.c fsnotify: create a wrapper fsnotify_find_inode_mark() 2024-04-04 16:24:16 +02:00
audit_watch.c fsnotify: create a wrapper fsnotify_find_inode_mark() 2024-04-04 16:24:16 +02:00
audit.c audit: Make use of str_enabled_disabled() helper 2024-09-03 16:35:16 -04:00
audit.h
auditfilter.c audit: use task_tgid_nr() instead of task_pid_nr() 2024-08-28 16:48:28 -04:00
auditsc.c audit: use task_tgid_nr() instead of task_pid_nr() 2024-08-28 16:48:28 -04:00
backtracetest.c backtracetest: add MODULE_DESCRIPTION() 2024-06-24 22:24:55 -07:00
bounds.c bounds: Use the right number of bits for power-of-two CONFIG_NR_CPUS 2024-04-29 08:29:29 -07:00
capability.c
cfi.c
compat.c
configs.c
context_tracking.c context_tracking, rcu: Rename rcu_dyntick trace event into rcu_watching 2024-08-15 21:30:43 +05:30
cpu_pm.c
cpu.c Updates for timers and timekeeping: 2024-09-17 07:25:37 +02:00
crash_core.c Document/kexec: generalize crash hotplug description 2024-09-01 20:43:37 -07:00
crash_reserve.c crash: fix crash memory reserve exceed system memory bug 2024-09-01 20:43:30 -07:00
cred.c cred: Use KMEM_CACHE() instead of kmem_cache_create() 2024-02-23 17:33:31 -05:00
delayacct.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
dma.c
elfcorehdr.c crash: remove dependency of FA_DUMP on CRASH_DUMP 2024-02-23 17:48:22 -08:00
exec_domain.c
exit.c ALong with the usual shower of singleton patches, notable patch series in 2024-09-21 07:29:05 -07:00
exit.h
extable.c
fail_function.c
fork.c fork: only invoke khugepaged, ksm hooks if no error 2024-10-28 21:40:39 -07:00
freezer.c sched/fair: Fix external p->on_rq users 2024-10-14 09:14:35 +02:00
gen_kheaders.sh kheaders: use command -v to test for existence of cpio 2024-05-30 01:13:20 +09:00
groups.c
hung_task.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
iomem.c
irq_work.c
jump_label.c jump_label: Fix static_key_slow_dec() yet again 2024-09-10 11:57:27 +02:00
kallsyms_internal.h kallsyms: get rid of code for absolute kallsyms 2024-07-20 16:33:21 +09:00
kallsyms_selftest.c kallsyms: Match symbols exactly with CONFIG_LTO_CLANG 2024-08-15 09:33:35 -07:00
kallsyms_selftest.h
kallsyms.c kallsyms: Match symbols exactly with CONFIG_LTO_CLANG 2024-08-15 09:33:35 -07:00
kcmp.c file: convert to SLAB_TYPESAFE_BY_RCU 2023-10-19 11:02:48 +02:00
Kconfig.freezer
Kconfig.hz
Kconfig.kexec crash: clean up kdump related config items 2024-02-23 17:48:22 -08:00
Kconfig.locks
Kconfig.preempt sched_ext: Build fix on !CONFIG_STACKTRACE[_SUPPORT] 2024-08-01 07:08:01 -10:00
kcov.c Updates for KCOV instrumentation on x86: 2024-09-17 12:40:34 +02:00
kexec_core.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kexec_elf.c
kexec_file.c kexec_file: fix elfcorehdr digest exclusion when CONFIG_CRASH_HOTPLUG=y 2024-09-01 17:59:01 -07:00
kexec_internal.h kexec: use atomic_try_cmpxchg_acquire() in kexec_trylock() 2024-09-01 20:43:23 -07:00
kexec.c crash: add a new kexec flag for hotplug support 2024-04-23 14:59:01 +10:00
kheaders.c
kprobes.c kprobes: Fix to check symbol prefixes correctly 2024-08-05 14:04:03 +09:00
ksyms_common.c
ksysfs.c profiling: remove prof_cpu_mask 2024-07-29 10:45:54 -07:00
kthread.c kthread: unpark only parked kthread 2024-10-09 12:47:19 -07:00
latencytop.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
Makefile mm: move kernel/numa.c to mm/ 2024-09-03 21:15:26 -07:00
module_signature.c
notifier.c
nsproxy.c introduce fd_file(), convert all accessors to it. 2024-08-12 22:00:43 -04:00
padata.c This update includes the following changes: 2024-09-16 06:28:28 +02:00
panic.c drm next for 6.12-rc1 2024-09-19 10:18:15 +02:00
params.c params: Fix multi-line comment style 2023-12-01 09:51:44 -08:00
pid_namespace.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
pid_sysctl.h sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
pid.c introduce fd_file(), convert all accessors to it. 2024-08-12 22:00:43 -04:00
profile.c profiling: remove profile=sleep support 2024-08-04 13:36:28 -07:00
ptrace.c ptrace_attach: shift send(SIGSTOP) into ptrace_set_stopped() 2024-02-22 15:38:52 -08:00
range.c
reboot.c kernel misc: Remove the now superfluous sentinel elements from ctl_table array 2024-04-24 09:43:53 +02:00
regset.c regset: use kvzalloc() for regset_get_alloc() 2024-04-25 21:07:03 -07:00
relay.c [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
resource_kunit.c resource, kunit: fix user-after-free in resource_test_region_intersects() 2024-10-09 12:47:19 -07:00
resource.c ALong with the usual shower of singleton patches, notable patch series in 2024-09-21 07:29:05 -07:00
rseq.c
scftorture.c scftorture: Make torture_type static 2024-05-30 15:31:51 -07:00
scs.c
seccomp.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
signal.c Revert "binfmt_elf, coredump: Log the reason of the failed core dumps" 2024-09-26 11:39:02 -07:00
smp.c smp: print only local CPU info when sched_clock goes backward 2024-08-15 00:06:48 +05:30
smpboot.c kthread: add kthread_stop_put 2023-10-04 10:41:57 -07:00
smpboot.h
softirq.c softirq: Remove unused 'action' parameter from action callback 2024-08-20 17:13:40 +02:00
stackleak.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
stacktrace.c stacktrace: fix kernel-doc typo 2023-12-29 12:22:29 -08:00
static_call_inline.c static_call: Replace pointless WARN_ON() in static_call_module_notify() 2024-09-06 16:29:22 +02:00
static_call.c
stop_machine.c rcu: Rename rcu_momentary_dyntick_idle() into rcu_momentary_eqs() 2024-08-15 21:30:42 +05:30
sys_ni.c Probes updates for v6.11: 2024-07-18 12:19:20 -07:00
sys.c struct fd layout change (and conversion to accessor helpers) 2024-09-23 09:35:36 -07:00
sysctl-test.c sysctl: Add module description to sysctl-testing 2024-06-03 15:20:37 +02:00
sysctl.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
task_work.c sched/core: Disable page allocation in task_tick_mm_cid() 2024-10-11 10:49:32 +02:00
taskstats.c introduce fd_file(), convert all accessors to it. 2024-08-12 22:00:43 -04:00
torture.c torture: Add MODULE_DESCRIPTION() 2024-05-30 15:31:38 -07:00
tracepoint.c tracepoint: Support iterating tracepoints in a loading module 2024-09-25 23:23:44 +09:00
tsacct.c tsacct: replace strncpy() with strscpy() 2024-07-12 16:39:53 -07:00
ucount.c sysctl changes for v6.10-rc1 2024-05-17 17:31:24 -07:00
uid16.c
uid16.h
umh.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
up.c
user_namespace.c user_namespace: use kmemdup_array() instead of kmemdup() for multiple allocation 2024-09-09 16:47:42 -07:00
user-return-notifier.c
user.c uidgid: make sure we fit into one cacheline 2024-09-12 12:16:09 +02:00
usermode_driver.c
utsname_sysctl.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
utsname.c
vhost_task.c vhost_task: Handle SIGKILL by flushing work and exiting 2024-05-22 08:31:15 -04:00
vmcore_info.c mm: support only one page_type per page 2024-09-03 21:15:43 -07:00
watch_queue.c introduce fd_file(), convert all accessors to it. 2024-08-12 22:00:43 -04:00
watchdog_buddy.c
watchdog_perf.c watchdog/perf: properly initialize the turbo mode timestamp and rearm counter 2024-07-17 21:11:34 -07:00
watchdog.c watchdog: handle the ENODEV failure case of lockup_detector_delay_init() separately 2024-09-01 20:43:32 -07:00
workqueue_internal.h
workqueue.c workqueue: Changes for v6.12 2024-09-18 06:59:44 +02:00