diff options
| author | Ming Lei <tom.leiming@gmail.com> | 2017-02-11 11:40:45 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-03-12 06:41:45 +0100 |
| commit | 50447afd96145b6d3d7aea412da178dce95f1f9b (patch) | |
| tree | cdccb8556fb2d5d8a2596bd74aea40afa0eeb09d /drivers/block/loop.c | |
| parent | a9b0c14ba1e4be94036c5725c144818a2d3be191 (diff) | |
block/loop: fix race between I/O and set_status
commit ecdd09597a57251323b0de50e3d45e69298c4a83 upstream.
Inside set_status, transfer need to setup again, so
we have to drain IO before the transition, otherwise
oops may be triggered like the following:
divide error: 0000 [#1] SMP KASAN
CPU: 0 PID: 2935 Comm: loop7 Not tainted 4.10.0-rc7+ #213
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
task: ffff88006ba1e840 task.stack: ffff880067338000
RIP: 0010:transfer_xor+0x1d1/0x440 drivers/block/loop.c:110
RSP: 0018:ffff88006733f108 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8800688d7000 RCX: 0000000000000059
RDX: 0000000000000000 RSI: 1ffff1000d743f43 RDI: ffff880068891c08
RBP: ffff88006733f160 R08: ffff8800688d7001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800688d7000
R13: ffff880067b7d000 R14: dffffc0000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88006d000000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006c17e0 CR3: 0000000066e3b000 CR4: 00000000001406f0
Call Trace:
lo_do_transfer drivers/block/loop.c:251 [inline]
lo_read_transfer drivers/block/loop.c:392 [inline]
do_req_filebacked drivers/block/loop.c:541 [inline]
loop_handle_cmd drivers/block/loop.c:1677 [inline]
loop_queue_work+0xda0/0x49b0 drivers/block/loop.c:1689
kthread_worker_fn+0x4c3/0xa30 kernel/kthread.c:630
kthread+0x326/0x3f0 kernel/kthread.c:227
ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430
Code: 03 83 e2 07 41 29 df 42 0f b6 04 30 4d 8d 44 24 01 38 d0 7f 08
84 c0 0f 85 62 02 00 00 44 89 f8 41 0f b6 48 ff 25 ff 01 00 00 99 <f7>
7d c8 48 63 d2 48 03 55 d0 48 89 d0 48 89 d7 48 c1 e8 03 83
RIP: transfer_xor+0x1d1/0x440 drivers/block/loop.c:110 RSP:
ffff88006733f108
---[ end trace 0166f7bd3b0c0933 ]---
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/block/loop.c')
| -rw-r--r-- | drivers/block/loop.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 4af818766797..ccc3acc0c5ba 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1097,9 +1097,12 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) return -EINVAL; + /* I/O need to be drained during transfer transition */ + blk_mq_freeze_queue(lo->lo_queue); + err = loop_release_xfer(lo); if (err) - return err; + goto exit; if (info->lo_encrypt_type) { unsigned int type = info->lo_encrypt_type; @@ -1114,12 +1117,14 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) err = loop_init_xfer(lo, xfer, info); if (err) - return err; + goto exit; if (lo->lo_offset != info->lo_offset || lo->lo_sizelimit != info->lo_sizelimit) - if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) - return -EFBIG; + if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) { + err = -EFBIG; + goto exit; + } loop_config_discard(lo); @@ -1156,7 +1161,9 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) /* update dio if lo_offset or transfer is changed */ __loop_update_dio(lo, lo->use_dio); - return 0; + exit: + blk_mq_unfreeze_queue(lo->lo_queue); + return err; } static int |