diff options
| author | Leonardo Bras <leobras.c@gmail.com> | 2020-05-12 18:45:35 -0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-06-02 20:59:07 +1000 |
| commit | af2876b501e42c3fb5174cac9dd02598436f0fdf (patch) | |
| tree | 4ec069414fb9c0383185ebc4fb9cf59b81857878 /arch/powerpc/kexec | |
| parent | b6eca183e23e7a6625a0d2cdb806b7cd1abcd2d2 (diff) | |
powerpc/crash: Use NMI context for printk when starting to crash
Currently, if printk lock (logbuf_lock) is held by other thread during
crash, there is a chance of deadlocking the crash on next printk, and
blocking a possibly desired kdump.
At the start of default_machine_crash_shutdown, make printk enter
NMI context, as it will use per-cpu buffers to store the message,
and avoid locking logbuf_lock.
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200512214533.93878-1-leobras.c@gmail.com
Diffstat (limited to 'arch/powerpc/kexec')
| -rw-r--r-- | arch/powerpc/kexec/crash.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c index d488311efab1..c9a889880214 100644 --- a/arch/powerpc/kexec/crash.c +++ b/arch/powerpc/kexec/crash.c @@ -311,6 +311,9 @@ void default_machine_crash_shutdown(struct pt_regs *regs) unsigned int i; int (*old_handler)(struct pt_regs *regs); + /* Avoid hardlocking with irresponsive CPU holding logbuf_lock */ + printk_nmi_enter(); + /* * This function is only called after the system * has panicked or is otherwise in a critical state. |