Oleg Nesterov 3820b0fac7 fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats ...

[ Upstream commit 7601df8031fd67310af891897ef6cc0df4209305 ]

lock_task_sighand() can trigger a hard lockup.  If NR_CPUS threads call
do_task_stat() at the same time and the process has NR_THREADS, it will
spin with irqs disabled O(NR_CPUS * NR_THREADS) time.

Change do_task_stat() to use sig->stats_lock to gather the statistics
outside of ->siglock protected section, in the likely case this code will
run lockless.

Link: https://lkml.kernel.org/r/20240123153357.GA21857@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>
[ Resolve minor conflicts ]
Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2024-12-09 10:31:41 +01:00

..

array.c

fs/proc: do_task_stat: use sig->stats_lock to gather the threads/children stats

2024-12-09 10:31:41 +01:00

base.c

proc: add config & param to block forcing mem writes

2024-10-10 11:57:27 +02:00

bootconfig.c

…

cmdline.c

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consoles.c

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cpuinfo.c

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devices.c

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fd.c

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fd.h

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generic.c

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inode.c

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internal.h

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interrupts.c

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Kconfig

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kcore.c

fs/proc/kcore.c: allow translation of physical memory addresses

2024-10-17 15:24:37 +02:00

kmsg.c

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loadavg.c

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Makefile

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meminfo.c

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namespaces.c

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nommu.c

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page.c

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proc_net.c

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proc_sysctl.c

sysctl: always initialize i_uid/i_gid

2024-08-11 12:47:13 +02:00

proc_tty.c

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root.c

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self.c

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softirqs.c

proc/softirqs: replace seq_printf with seq_put_decimal_ull_width

2024-12-09 10:31:39 +01:00

stat.c

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task_mmu.c

fs/proc/task_mmu: properly detect PM_MMAP_EXCLUSIVE per page of PMD-mapped THPs

2024-08-03 08:54:09 +02:00

task_nommu.c

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thread_self.c

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uptime.c

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util.c

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version.c

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vmcore.c

fs/proc: fix compile warning about variable 'vmcore_mmap_ops'

2024-11-14 13:19:39 +01:00