If 'chip->state == FL_SYNCING', we will 'goto retry' with the mutex
'&shared->lock' already taken.
In such a case, the 'mutex_lock' at line 927 can never succeed.
In order to avoid a deadlock, move the 'mutex_lock(&shared->lock)' at the
very end of the block.
This has been spotted with the following coccinelle script:
@find@
expression x, t;
@@
mutex_lock(x);
... when != mutex_unlock(x)
mutex_lock(t);
@@
expression find.t;
expression find.x;
@@
* mutex_lock(t);
... when != mutex_unlock(t)
* mutex_lock(x);
Fixes: 3afe7eb37f4d ("[MTD] [NOR] fix cfi_cmdset_0001 FL_SYNCING race (take 2)")
Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
---
Review carefuly, untested.
---
drivers/mtd/chips/cfi_cmdset_0001.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index 5e1b68cbcd0a..bddf407a366d 100644
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -952,7 +952,6 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
mutex_unlock(&contender->mutex);
return ret;
}
- mutex_lock(&shared->lock);
/* We should not own chip if it is already
* in FL_SYNCING state. Put contender and retry. */
@@ -962,6 +961,8 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
goto retry;
}
mutex_unlock(&contender->mutex);
+
+ mutex_lock(&shared->lock);
}
/* Check if we already have suspended erase
--
2.14.1
--
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