From: Konrad Rzeszutek Wilk Date: Fri, 25 May 2012 20:11:09 +0000 (-0400) Subject: xen/blkback: Copy id field when doing BLKIF_DISCARD. X-Git-Tag: firefly_0821_release~3680^2~2262^2~26^2~1 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8c9ce606a60e4a0cb447bdc082ce383b96b227b4;p=firefly-linux-kernel-4.4.55.git xen/blkback: Copy id field when doing BLKIF_DISCARD. We weren't copying the id field so when we sent the response back to the frontend (especially with a 64-bit host and 32-bit guest), we ended up using a random value. This lead to the frontend crashing as it would try to pass to __blk_end_request_all a NULL 'struct request' (b/c it would use the 'id' to find the proper 'struct request' in its shadow array) and end up crashing: BUG: unable to handle kernel NULL pointer dereference at 000000e4 IP: [] __blk_end_request_all+0xc/0x40 .. snip.. EIP is at __blk_end_request_all+0xc/0x40 .. snip.. [] blkif_interrupt+0x172/0x330 [xen_blkfront] This fixes the bug by passing in the proper id for the response. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=824641 CC: stable@kernel.org Tested-by: William Dauchy Acked-by: Stefano Stabellini Signed-off-by: Konrad Rzeszutek Wilk --- diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index 773cf27dc23f..9ad3b5ec1dc1 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -257,6 +257,7 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst, break; case BLKIF_OP_DISCARD: dst->u.discard.flag = src->u.discard.flag; + dst->u.discard.id = src->u.discard.id; dst->u.discard.sector_number = src->u.discard.sector_number; dst->u.discard.nr_sectors = src->u.discard.nr_sectors; break; @@ -287,6 +288,7 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst, break; case BLKIF_OP_DISCARD: dst->u.discard.flag = src->u.discard.flag; + dst->u.discard.id = src->u.discard.id; dst->u.discard.sector_number = src->u.discard.sector_number; dst->u.discard.nr_sectors = src->u.discard.nr_sectors; break;