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panic: unset panic_on_warn inside panic() 

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: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: Marco 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Tiezhu Yang 2022-03-23 16:06:51 -07:00 committed by Linus Torvalds
parent ae6694c1aa
commit 1a2383e8b8
1 changed files with 11 additions and 9 deletions
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20
kernel/panic.c
View File

@ -185,6 +185,16 @@ 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
@ -576,16 +586,8 @@ 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();