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authorKees Cook <keescook@chromium.org>2018-11-30 14:36:58 -0800
committerKees Cook <keescook@chromium.org>2018-12-03 17:11:02 -0800
commitea84b580b95521644429cc6748b6c2bf27c8b0f3 (patch)
tree85cffd2d9d61cd2ee0fe379384f9f2fe12292598 /fs/pstore/ram.c
parent69596433bc28a4642bdc84676f44cfa3b16d0588 (diff)
downloadlinux-ea84b580b95521644429cc6748b6c2bf27c8b0f3.tar.gz
pstore: Convert buf_lock to semaphore
Instead of running with interrupts disabled, use a semaphore. This should
make it easier for backends that may need to sleep (e.g. EFI) when
performing a write:

|BUG: sleeping function called from invalid context at kernel/sched/completion.c:99
|in_atomic(): 1, irqs_disabled(): 1, pid: 2236, name: sig-xstate-bum
|Preemption disabled at:
|[<ffffffff99d60512>] pstore_dump+0x72/0x330
|CPU: 26 PID: 2236 Comm: sig-xstate-bum Tainted: G      D           4.20.0-rc3 #45
|Call Trace:
| dump_stack+0x4f/0x6a
| ___might_sleep.cold.91+0xd3/0xe4
| __might_sleep+0x50/0x90
| wait_for_completion+0x32/0x130
| virt_efi_query_variable_info+0x14e/0x160
| efi_query_variable_store+0x51/0x1a0
| efivar_entry_set_safe+0xa3/0x1b0
| efi_pstore_write+0x109/0x140
| pstore_dump+0x11c/0x330
| kmsg_dump+0xa4/0xd0
| oops_exit+0x22/0x30
...

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Fixes: 21b3ddd39fee ("efi: Don't use spinlocks for efi vars")
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'fs/pstore/ram.c')
-rw-r--r--fs/pstore/ram.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 202eaa82bcc6..e6d9560ea455 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -815,7 +815,6 @@ static int ramoops_probe(struct platform_device *pdev)
 		err = -ENOMEM;
 		goto fail_clear;
 	}
-	spin_lock_init(&cxt->pstore.buf_lock);
 
 	cxt->pstore.flags = PSTORE_FLAGS_DMESG;
 	if (cxt->console_size)