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
configs
debug
dma
entry
events	sched/fair: Fix external p->on_rq users	2024-10-14 09:14:35 +02:00
futex
gcov
irq
kcsan
livepatch
locking
module
power
printk
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
async.c
audit.c
audit.h
audit_fsnotify.c
audit_tree.c
audit_watch.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cfi.c
compat.c
configs.c
context_tracking.c
cpu.c
cpu_pm.c
crash_core.c
crash_reserve.c
cred.c
delayacct.c
dma.c
elfcorehdr.c
exec_domain.c
exit.c
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
groups.c
hung_task.c
iomem.c
irq_work.c
jump_label.c
kallsyms.c
kallsyms_internal.h
kallsyms_selftest.c
kallsyms_selftest.h
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.kexec
Kconfig.locks
Kconfig.preempt
kcov.c
kexec.c
kexec_core.c
kexec_elf.c
kexec_file.c
kexec_internal.h
kheaders.c
kprobes.c
ksyms_common.c
ksysfs.c
kthread.c	kthread: unpark only parked kthread	2024-10-09 12:47:19 -07:00
latencytop.c
Makefile
module_signature.c
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid.c
pid_namespace.c
pid_sysctl.h
profile.c
ptrace.c
range.c
reboot.c
regset.c
relay.c
resource.c
resource_kunit.c	resource, kunit: fix user-after-free in resource_test_region_intersects()	2024-10-09 12:47:19 -07:00
rseq.c
scftorture.c
scs.c
seccomp.c
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c
stackleak.c
stacktrace.c
static_call.c
static_call_inline.c
stop_machine.c
sys.c
sys_ni.c
sysctl-test.c
sysctl.c
task_work.c	sched/core: Disable page allocation in task_tick_mm_cid()	2024-10-11 10:49:32 +02:00
taskstats.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user-return-notifier.c
user.c
user_namespace.c
usermode_driver.c
utsname.c
utsname_sysctl.c
vhost_task.c
vmcore_info.c
watch_queue.c
watchdog.c
watchdog_buddy.c
watchdog_perf.c
workqueue.c
workqueue_internal.h