Commit f6c1d9ea authored by Tiezhu Yang's avatar Tiezhu Yang Committed by sanglipeng
Browse files

panic: unset panic_on_warn inside panic() 

stable inclusion
from stable-v5.10.166
commit 590ba6fee0956127b7ec62af3a658ed71d175f83
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=590ba6fee0956127b7ec62af3a658ed71d175f83

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

commit 1a2383e8 upstream.

In the current code, the following three places need to unset
panic_on_warn before calling panic() to avoid recursive panics:

kernel/kcsan/report.c: print_report()
kernel/sched/core.c: __schedule_bug()
mm/kfence/report.c: kfence_report_error()

In order to avoid copy-pasting "panic_on_warn = 0" all over the places,
it is better to move it inside panic() and then remove it from the other
places.

Link: https://lkml.kernel.org/r/1644324666-15947-4-git-send-email-yangtiezhu@loongson.cn


Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Xuefeng Li <lixuefeng@loongson.cn>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.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 787c0558

kernel/panic.c

+11 −9
Original line number Diff line number Diff line
@@ -207,6 +207,16 @@ void panic(const char *fmt, ...) 
	int old_cpu, this_cpu;

	bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;



	if (panic_on_warn) {

		/*

		 * This thread may hit another WARN() in the panic path.

		 * Resetting this prevents additional WARN() from panicking the

		 * system on this thread.  Other threads are blocked by the

		 * panic_mutex in panic().

		 */

		panic_on_warn = 0;

	}



	/*

	 * Disable local interrupts. This will prevent panic_smp_self_stop

	 * from deadlocking the first cpu that invokes the panic, since
@@ -645,16 +655,8 @@ void __warn(const char *file, int line, void *caller, unsigned taint, 
	if (regs)

		show_regs(regs);



	if (panic_on_warn) {

		/*

		 * This thread may hit another WARN() in the panic path.

		 * Resetting this prevents additional WARN() from panicking the

		 * system on this thread.  Other threads are blocked by the

		 * panic_mutex in panic().

		 */

		panic_on_warn = 0;

	if (panic_on_warn)

		panic("panic_on_warn set ...\n");

	}



	if (!regs)

		dump_stack();