[PATCH 4.14 153/157] block: Fix cloning of requests with a special payload

From: Greg Kroah-Hartman
Date: Sun Jul 01 2018 - 13:30:03 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Bart Van Assche <bart.vanassche@xxxxxxx>

commit 297ba57dcdec7ea37e702bcf1a577ac32a034e21 upstream.

This patch avoids that removing a path controlled by the dm-mpath driver
while mkfs is running triggers the following kernel bug:

kernel BUG at block/blk-core.c:3347!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 20 PID: 24369 Comm: mkfs.ext4 Not tainted 4.18.0-rc1-dbg+ #2
RIP: 0010:blk_end_request_all+0x68/0x70
Call Trace:
<IRQ>
dm_softirq_done+0x326/0x3d0 [dm_mod]
blk_done_softirq+0x19b/0x1e0
__do_softirq+0x128/0x60d
irq_exit+0x100/0x110
smp_call_function_single_interrupt+0x90/0x330
call_function_single_interrupt+0xf/0x20
</IRQ>

Fixes: f9d03f96b988 ("block: improve handling of the magic discard payload")
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
block/blk-core.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3150,6 +3150,10 @@ static void __blk_rq_prep_clone(struct r
dst->cpu = src->cpu;
dst->__sector = blk_rq_pos(src);
dst->__data_len = blk_rq_bytes(src);
+ if (src->rq_flags & RQF_SPECIAL_PAYLOAD) {
+ dst->rq_flags |= RQF_SPECIAL_PAYLOAD;
+ dst->special_vec = src->special_vec;
+ }
dst->nr_phys_segments = src->nr_phys_segments;
dst->ioprio = src->ioprio;
dst->extra_len = src->extra_len;