| Message ID | 20221107033956.3276891-1-yebin@huaweicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: fix crash in 'blk_mq_elv_switch_none' | expand |
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
ping... On 2022/11/7 11:39, Ye Bin wrote: > From: Ye Bin <yebin10@huawei.com> > > Syzbot found the following issue: > general protection fault, probably for non-canonical address 0xdffffc000000001d: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef] > CPU: 0 PID: 5234 Comm: syz-executor931 Not tainted 6.1.0-rc3-next-20221102-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 > RIP: 0010:__elevator_get block/elevator.h:94 [inline] > RIP: 0010:blk_mq_elv_switch_none block/blk-mq.c:4593 [inline] > RIP: 0010:__blk_mq_update_nr_hw_queues block/blk-mq.c:4658 [inline] > RIP: 0010:blk_mq_update_nr_hw_queues+0x304/0xe40 block/blk-mq.c:4709 > RSP: 0018:ffffc90003cdfc08 EFLAGS: 00010206 > RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000 > RDX: 000000000000001d RSI: 0000000000000002 RDI: 00000000000000e8 > RBP: ffff88801dbd0000 R08: ffff888027c89398 R09: ffffffff8de2e517 > R10: fffffbfff1bc5ca2 R11: 0000000000000000 R12: ffffc90003cdfc70 > R13: ffff88801dbd0008 R14: ffff88801dbd03f8 R15: ffff888027c89380 > FS: 0000555557259300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000005d84c8 CR3: 000000007a7cb000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > nbd_start_device+0x153/0xc30 drivers/block/nbd.c:1355 > nbd_start_device_ioctl drivers/block/nbd.c:1405 [inline] > __nbd_ioctl drivers/block/nbd.c:1481 [inline] > nbd_ioctl+0x5a1/0xbd0 drivers/block/nbd.c:1521 > blkdev_ioctl+0x36e/0x800 block/ioctl.c:614 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:870 [inline] > __se_sys_ioctl fs/ioctl.c:856 [inline] > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > As after dd6f7f17bf58 commit move '__elevator_get(qe->type)' before set > 'qe->type', so will lead to access wild pointer. > To solve above issue get 'qe->type' after set 'qe->type'. > > Reported-by: syzbot+746a4eece09f86bc39d7@syzkaller.appspotmail.com > Fixes:dd6f7f17bf58("block: add proper helpers for elevator_type module refcount management") > Signed-off-by: Ye Bin <yebin10@huawei.com> > --- > block/blk-mq.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 2757368dc83f..3173d621f1f7 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -4589,9 +4589,9 @@ static bool blk_mq_elv_switch_none(struct list_head *head, > > INIT_LIST_HEAD(&qe->node); > qe->q = q; > + qe->type = q->elevator->type; > /* keep a reference to the elevator module as we'll switch back */ > __elevator_get(qe->type); > - qe->type = q->elevator->type; > list_add(&qe->node, head); > elevator_disable(q); > mutex_unlock(&q->sysfs_lock);
On Mon, 7 Nov 2022 11:39:56 +0800, Ye Bin wrote: > From: Ye Bin <yebin10@huawei.com> > > Syzbot found the following issue: > general protection fault, probably for non-canonical address 0xdffffc000000001d: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef] > CPU: 0 PID: 5234 Comm: syz-executor931 Not tainted 6.1.0-rc3-next-20221102-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 > RIP: 0010:__elevator_get block/elevator.h:94 [inline] > RIP: 0010:blk_mq_elv_switch_none block/blk-mq.c:4593 [inline] > RIP: 0010:__blk_mq_update_nr_hw_queues block/blk-mq.c:4658 [inline] > RIP: 0010:blk_mq_update_nr_hw_queues+0x304/0xe40 block/blk-mq.c:4709 > RSP: 0018:ffffc90003cdfc08 EFLAGS: 00010206 > RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000 > RDX: 000000000000001d RSI: 0000000000000002 RDI: 00000000000000e8 > RBP: ffff88801dbd0000 R08: ffff888027c89398 R09: ffffffff8de2e517 > R10: fffffbfff1bc5ca2 R11: 0000000000000000 R12: ffffc90003cdfc70 > R13: ffff88801dbd0008 R14: ffff88801dbd03f8 R15: ffff888027c89380 > FS: 0000555557259300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000005d84c8 CR3: 000000007a7cb000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > nbd_start_device+0x153/0xc30 drivers/block/nbd.c:1355 > nbd_start_device_ioctl drivers/block/nbd.c:1405 [inline] > __nbd_ioctl drivers/block/nbd.c:1481 [inline] > nbd_ioctl+0x5a1/0xbd0 drivers/block/nbd.c:1521 > blkdev_ioctl+0x36e/0x800 block/ioctl.c:614 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:870 [inline] > __se_sys_ioctl fs/ioctl.c:856 [inline] > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > [...] Applied, thanks! [1/1] block: fix crash in 'blk_mq_elv_switch_none' commit: 90b0296ece4bd8f70419f0addc1171be6feee195 Best regards,
diff --git a/block/blk-mq.c b/block/blk-mq.c index 2757368dc83f..3173d621f1f7 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4589,9 +4589,9 @@ static bool blk_mq_elv_switch_none(struct list_head *head, INIT_LIST_HEAD(&qe->node); qe->q = q; + qe->type = q->elevator->type; /* keep a reference to the elevator module as we'll switch back */ __elevator_get(qe->type); - qe->type = q->elevator->type; list_add(&qe->node, head); elevator_disable(q); mutex_unlock(&q->sysfs_lock);