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authorRusty Russell <rusty@rustcorp.com.au>2013-10-14 09:38:45 +0200
committerRusty Russell <rusty@rustcorp.com.au>2013-10-17 02:25:35 +0200
commitbb478d8b167cf875565ac7d927ffbdc0b6d280e8 (patch)
tree896308db8cb966bb6e92a1664fd3a1a939d67814
parentvirtio: pm: use CONFIG_PM_SLEEP instead of CONFIG_PM (diff)
downloadlinux-bb478d8b167cf875565ac7d927ffbdc0b6d280e8.tar.xz
linux-bb478d8b167cf875565ac7d927ffbdc0b6d280e8.zip
virtio_ring: plug kmemleak false positive.
unreferenced object 0xffff88003d467e20 (size 32): comm "softirq", pid 0, jiffies 4295197765 (age 6.364s) hex dump (first 32 bytes): 28 19 bf 3d 00 00 00 00 0c 00 00 00 01 00 01 00 (..=............ 02 dc 51 3c 00 00 00 00 56 00 00 00 00 00 00 00 ..Q<....V....... backtrace: [<ffffffff8152db19>] kmemleak_alloc+0x59/0xc0 [<ffffffff81102e93>] __kmalloc+0xf3/0x180 [<ffffffff812db5d6>] vring_add_indirect+0x36/0x280 [<ffffffff812dc59f>] virtqueue_add_outbuf+0xbf/0x4e0 [<ffffffff813a8b30>] start_xmit+0x1a0/0x3b0 [<ffffffff81445861>] dev_hard_start_xmit+0x2d1/0x4d0 [<ffffffff81460052>] sch_direct_xmit+0xf2/0x1c0 [<ffffffff81445c28>] dev_queue_xmit+0x1c8/0x460 [<ffffffff814e3187>] ip6_finish_output2+0x1d7/0x470 [<ffffffff814e34b0>] ip6_finish_output+0x90/0xb0 [<ffffffff814e3507>] ip6_output+0x37/0xb0 [<ffffffff815021eb>] igmp6_send+0x2db/0x470 [<ffffffff81502645>] igmp6_timer_handler+0x95/0xa0 [<ffffffff8104b57c>] call_timer_fn+0x2c/0x90 [<ffffffff8104b7ba>] run_timer_softirq+0x1da/0x1f0 [<ffffffff81045721>] __do_softirq+0xd1/0x1b0 Address gets embedded in a descriptor via virt_to_phys(). See detach_buf, which frees it: if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) kfree(phys_to_virt(vq->vring.desc[i].addr)); Reported-by: Christoph Paasch <christoph.paasch@uclouvain.be> Fix-suggested-by: Christoph Paasch <christoph.paasch@uclouvain.be> Typing-done-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--drivers/virtio/virtio_ring.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 6b4a4db4404d..6547d46171b3 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -173,6 +173,8 @@ static inline int vring_add_indirect(struct vring_virtqueue *vq,
head = vq->free_head;
vq->vring.desc[head].flags = VRING_DESC_F_INDIRECT;
vq->vring.desc[head].addr = virt_to_phys(desc);
+ /* kmemleak gives a false positive, as it's hidden by virt_to_phys */
+ kmemleak_ignore(desc);
vq->vring.desc[head].len = i * sizeof(struct vring_desc);
/* Update free pointer */