1. 13 Feb, 2017 1 commit
    • Ming Lei's avatar
      block/loop: fix race between I/O and set_status · ecdd0959
      Ming Lei authored
      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: default avatarDmitry Vyukov <dvyukov@google.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
      Tested-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      ecdd0959
  2. 07 Feb, 2017 2 commits
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