| Message ID | 1540918161-31283-1-git-send-email-manjunath.b.patil@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] xen-blkfront: fix kernel panic with negotiate_mq error path | expand |
On 30/10/2018 17:49, Manjunath Patil wrote: > info->nr_rings isn't adjusted in case of ENOMEM error from > negotiate_mq(). This leads to kernel panic in error path. > > Typical call stack involving panic - > #8 page_fault at ffffffff8175936f > [exception RIP: blkif_free_ring+33] > RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 > ... > #9 blkif_free at ffffffffa0149aaa [xen_blkfront] > #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] > #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] > #12 xenbus_otherend_changed at ffffffff81424670 > #13 backend_changed at ffffffff81426dc3 > #14 xenwatch_thread at ffffffff81422f29 > #15 kthread at ffffffff810abe6a > #16 ret_from_fork at ffffffff81754078 > > Cc: stable@vger.kernel.org > Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of new VBDs") > Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Juergen
On Tue, Oct 30, 2018 at 09:49:21AM -0700, Manjunath Patil wrote: > info->nr_rings isn't adjusted in case of ENOMEM error from > negotiate_mq(). This leads to kernel panic in error path. > > Typical call stack involving panic - > #8 page_fault at ffffffff8175936f > [exception RIP: blkif_free_ring+33] > RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 > ... > #9 blkif_free at ffffffffa0149aaa [xen_blkfront] > #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] > #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] > #12 xenbus_otherend_changed at ffffffff81424670 > #13 backend_changed at ffffffff81426dc3 > #14 xenwatch_thread at ffffffff81422f29 > #15 kthread at ffffffff810abe6a > #16 ret_from_fork at ffffffff81754078 > > Cc: stable@vger.kernel.org > Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of new VBDs") > Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Thanks, Roger.
On 30/10/2018 17:49, Manjunath Patil wrote: > info->nr_rings isn't adjusted in case of ENOMEM error from > negotiate_mq(). This leads to kernel panic in error path. > > Typical call stack involving panic - > #8 page_fault at ffffffff8175936f > [exception RIP: blkif_free_ring+33] > RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 > ... > #9 blkif_free at ffffffffa0149aaa [xen_blkfront] > #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] > #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] > #12 xenbus_otherend_changed at ffffffff81424670 > #13 backend_changed at ffffffff81426dc3 > #14 xenwatch_thread at ffffffff81422f29 > #15 kthread at ffffffff810abe6a > #16 ret_from_fork at ffffffff81754078 > > Cc: stable@vger.kernel.org > Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of new VBDs") > Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> Pushed to xen.git for-linus-4.20a Juergen
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 429d201..5d84da2 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1919,6 +1919,7 @@ static int negotiate_mq(struct blkfront_info *info) GFP_KERNEL); if (!info->rinfo) { xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); + info->nr_rings = 0; return -ENOMEM; }
info->nr_rings isn't adjusted in case of ENOMEM error from negotiate_mq(). This leads to kernel panic in error path. Typical call stack involving panic - #8 page_fault at ffffffff8175936f [exception RIP: blkif_free_ring+33] RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 ... #9 blkif_free at ffffffffa0149aaa [xen_blkfront] #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] #12 xenbus_otherend_changed at ffffffff81424670 #13 backend_changed at ffffffff81426dc3 #14 xenwatch_thread at ffffffff81422f29 #15 kthread at ffffffff810abe6a #16 ret_from_fork at ffffffff81754078 Cc: stable@vger.kernel.org Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of new VBDs") Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> --- drivers/block/xen-blkfront.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)