From: Tiezhu Yang yangtiezhu@loongson.cn
commit 1a2383e8b84c0451fd9b1eec3b9aab16f30b597c 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@loong... 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 Signed-off-by: Eric Biggers ebiggers@google.com --- kernel/panic.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/kernel/panic.c b/kernel/panic.c index 5ee281b996f9e..5ed1ad06f9a34 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -208,6 +208,16 @@ 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 @@ -616,16 +626,8 @@ 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();