Commit a58905ef authored by Kees Cook's avatar Kees Cook Committed by sanglipeng
Browse files

panic: Introduce warn_limit 

stable inclusion
from stable-v5.10.166
commit 8c99d4c4c192770e7ea622220e36f53b85152a75
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7TH9O

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8c99d4c4c192770e7ea622220e36f53b85152a75



--------------------------------

commit 9fc9e278 upstream.

Like oops_limit, add warn_limit for limiting the number of warnings when
panic_on_warn is not set.

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: tangmeng <tangmeng@uniontech.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-doc@vger.kernel.org
Reviewed-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221117234328.594699-5-keescook@chromium.org


Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarsanglipeng <sanglipeng1@jd.com>
parent 6df0a690

Documentation/admin-guide/sysctl/kernel.rst

+10 −0
Original line number Diff line number Diff line
@@ -1490,6 +1490,16 @@ entry will default to 2 instead of 0. 
2 Unprivileged calls to ``bpf()`` are disabled

= =============================================================





warn_limit

==========



Number of kernel warnings after which the kernel should panic when

``panic_on_warn`` is not set. Setting this to 0 disables checking

the warning count. Setting this to 1 has the same effect as setting

``panic_on_warn=1``. The default value is 0.





watchdog

========

kernel/panic.c

+14 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ bool crash_kexec_post_notifiers; 
int panic_on_warn __read_mostly;

unsigned long panic_on_taint;

bool panic_on_taint_nousertaint = false;

static unsigned int warn_limit __read_mostly;



int panic_timeout = CONFIG_PANIC_TIMEOUT;

EXPORT_SYMBOL_GPL(panic_timeout);
@@ -85,6 +86,13 @@ static struct ctl_table kern_panic_table[] = { 
		.extra2         = SYSCTL_ONE,

	},

#endif

	{

		.procname       = "warn_limit",

		.data           = &warn_limit,

		.maxlen         = sizeof(warn_limit),

		.mode           = 0644,

		.proc_handler   = proc_douintvec,

	},

	{ }

};
@@ -194,8 +202,14 @@ static void panic_print_sys_info(void) 


void check_panic_on_warn(const char *origin)

{

	static atomic_t warn_count = ATOMIC_INIT(0);



	if (panic_on_warn)

		panic("%s: panic_on_warn set ...\n", origin);



	if (atomic_inc_return(&warn_count) >= READ_ONCE(warn_limit) && warn_limit)

		panic("%s: system warned too often (kernel.warn_limit is %d)",

		      origin, warn_limit);

}



/**