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authorDon Zickus <dzickus@redhat.com>2011-08-12 10:54:51 -0700
committerTony Luck <tony.luck@intel.com>2011-08-16 11:55:58 -0700
commitabd4d5587be911f63592537284dad78766d97d62 (patch)
tree50d88b64ded1189d6c816a1f90124a05354914ba /drivers/acpi
parent6dda9266913ad57e09afc1a10d6473f10c806a63 (diff)
downloadlinux-abd4d5587be911f63592537284dad78766d97d62.tar.bz2
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 <dzickus@redhat.com> Acked-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/apei/erst.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index 2ca59dc69f7f..5e820ea35570 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -1165,7 +1165,7 @@ static int __init erst_init(void)
goto err_release_erange;
buf = kmalloc(erst_erange.size, GFP_KERNEL);
- mutex_init(&erst_info.buf_mutex);
+ spin_lock_init(&erst_info.buf_lock);
if (buf) {
erst_info.buf = buf + sizeof(struct cper_pstore_record);
erst_info.bufsize = erst_erange.size -