Oleg Nesterov c7f9c3e94e fs/proc: do_task_stat: move thread_group_cputime_adjusted() outside of lock_task_sighand() ... commit 60f92acb60 upstream. Patch series "fs/proc: do_task_stat: use sig->stats_". do_task_stat() has the same problem as getrusage() had before "getrusage: use sig->stats_lock rather than lock_task_sighand()": a hard lockup. If NR_CPUS threads call lock_task_sighand() at the same time and the process has NR_THREADS, spin_lock_irq will spin with irqs disabled O(NR_CPUS * NR_THREADS) time. This patch (of 3): thread_group_cputime() does its own locking, we can safely shift thread_group_cputime_adjusted() which does another for_each_thread loop outside of ->siglock protected section. Not only this removes for_each_thread() from the critical section with irqs disabled, this removes another case when stats_lock is taken with siglock held. We want to remove this dependency, then we can change the users of stats_lock to not disable irqs. Link: https://lkml.kernel.org/r/20240123153313.GA21832@redhat.com Link: https://lkml.kernel.org/r/20240123153355.GA21854@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Dylan Hatch <dylanbhatch@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2024-02-23 09:12:47 +01:00
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array.c	fs/proc: do_task_stat: move thread_group_cputime_adjusted() outside of lock_task_sighand()	2024-02-23 09:12:47 +01:00
base.c
bootconfig.c
cmdline.c
consoles.c
cpuinfo.c
devices.c
fd.c
fd.h
generic.c
inode.c
internal.h	proc: nommu: fix empty /proc/<pid>/maps	2023-10-06 14:56:42 +02:00
interrupts.c
Kconfig
kcore.c
kmsg.c
loadavg.c
Makefile
meminfo.c
namespaces.c
nommu.c
page.c
proc_net.c
proc_sysctl.c	watchdog: move softlockup_panic back to early_param	2023-11-28 17:07:09 +00:00
proc_tty.c
root.c
self.c
softirqs.c
stat.c
task_mmu.c
task_nommu.c	proc: nommu: fix empty /proc/<pid>/maps	2023-10-06 14:56:42 +02:00
thread_self.c
uptime.c
util.c
version.c
vmcore.c