From abd4d5587be911f63592537284dad78766d97d62 Mon Sep 17 00:00:00 2001 From: Don Zickus Date: Fri, 12 Aug 2011 10:54:51 -0700 Subject: pstore: change mutex locking to spin_locks pstore was using mutex locking to protect read/write access to the backend plug-ins. This causes problems when pstore is executed in an NMI context through panic() -> kmsg_dump(). This patch changes the mutex to a spin_lock_irqsave then also checks to see if we are in an NMI context. If we are in an NMI and can't get the lock, just print a message stating that and blow by the locking. All this is probably a hack around the bigger locking problem but it solves my current situation of trying to sleep in an NMI context. Tested by loading the lkdtm module and executing a HARDLOCKUP which will cause the machine to panic inside the nmi handler. Signed-off-by: Don Zickus Acked-by: Matthew Garrett Signed-off-by: Tony Luck --- drivers/firmware/efivars.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/firmware') diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index eb80b549ed8d..be8bcb035e2a 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -978,7 +978,7 @@ int register_efivars(struct efivars *efivars, if (efivars->efi_pstore_info.buf) { efivars->efi_pstore_info.bufsize = 1024; efivars->efi_pstore_info.data = efivars; - mutex_init(&efivars->efi_pstore_info.buf_mutex); + spin_lock_init(&efivars->efi_pstore_info.buf_lock); pstore_register(&efivars->efi_pstore_info); } -- cgit v1.2.3