diff options
| author | Don Zickus <dzickus@redhat.com> | 2011-08-12 10:54:51 -0700 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2011-08-16 11:55:58 -0700 |
| commit | abd4d5587be911f63592537284dad78766d97d62 (patch) | |
| tree | 50d88b64ded1189d6c816a1f90124a05354914ba /drivers | |
| parent | 6dda9266913ad57e09afc1a10d6473f10c806a63 (diff) | |
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')
| -rw-r--r-- | drivers/acpi/apei/erst.c | 2 | ||||
| -rw-r--r-- | drivers/firmware/efivars.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c index 2ca59dc69f7..5e820ea3557 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 - diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index eb80b549ed8..be8bcb035e2 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); } |