* [PATCH 4.8-4.11] dm io: fix duplicate bio completion due to missing ref count
@ 2018-03-06 13:30 Mikulas Patocka
2018-03-07 17:26 ` Greg Kroah-Hartman
0 siblings, 1 reply; 2+ messages in thread
From: Mikulas Patocka @ 2018-03-06 13:30 UTC (permalink / raw)
To: Greg Kroah-Hartman, stable; +Cc: Mike Snitzer, Zhang Yi
This is backport of the upstream commit that fixes memory corruption in
dm-io. It is suitable for stable kernels 4.8 to 4.11. (the bug was already
fixed in 4.12)
Mikulas
commit feb7695fe9fb83084aa29de0094774f4c9d4c9fc
Author: Mike Snitzer <snitzer@redhat.com>
Date: Tue Jun 20 19:14:30 2017 -0400
dm io: fix duplicate bio completion due to missing ref count
If only a subset of the devices associated with multiple regions support
a given special operation (eg. DISCARD) then the dec_count() that is
used to set error for the region must increment the io->count.
Otherwise, when the dec_count() is called it can cause the dm-io
caller's bio to be completed multiple times. As was reported against
the dm-mirror target that had mirror legs with a mix of discard
capabilities.
Bug: https://bugzilla.kernel.org/show_bug.cgi?id=196077
Reported-by: Zhang Yi <yizhan@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/dm-io.c | 1 +
1 file changed, 1 insertion(+)
Index: linux-stable/drivers/md/dm-io.c
===================================================================
--- linux-stable.orig/drivers/md/dm-io.c 2018-03-06 14:13:59.000000000 +0100
+++ linux-stable/drivers/md/dm-io.c 2018-03-06 14:14:23.000000000 +0100
@@ -316,6 +316,7 @@ static void do_region(int op, int op_fla
special_cmd_max_sectors = q->limits.max_write_same_sectors;
if ((op == REQ_OP_DISCARD || op == REQ_OP_WRITE_SAME) &&
special_cmd_max_sectors == 0) {
+ atomic_inc(&io->count);
dec_count(io, region, -EOPNOTSUPP);
return;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH 4.8-4.11] dm io: fix duplicate bio completion due to missing ref count
2018-03-06 13:30 [PATCH 4.8-4.11] dm io: fix duplicate bio completion due to missing ref count Mikulas Patocka
@ 2018-03-07 17:26 ` Greg Kroah-Hartman
0 siblings, 0 replies; 2+ messages in thread
From: Greg Kroah-Hartman @ 2018-03-07 17:26 UTC (permalink / raw)
To: Mikulas Patocka; +Cc: stable, Mike Snitzer, Zhang Yi
On Tue, Mar 06, 2018 at 08:30:35AM -0500, Mikulas Patocka wrote:
> This is backport of the upstream commit that fixes memory corruption in
> dm-io. It is suitable for stable kernels 4.8 to 4.11. (the bug was already
> fixed in 4.12)
Now applied.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-03-06 13:30 [PATCH 4.8-4.11] dm io: fix duplicate bio completion due to missing ref count Mikulas Patocka
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