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  1. 03 Dec, 2018 5 commits
    • Peter Maydell's avatar
      Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging · 3af8c4be
      Peter Maydell authored 
      

Block layer patches:

- mirror: Fix deadlock

# gpg: Signature made Mon 03 Dec 2018 16:57:33 GMT
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  iotests: simple mirror test with kvm on 1G image
  mirror: fix dead-lock
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
      3af8c4be
    • Vladimir Sementsov-Ogievskiy's avatar
      iotests: simple mirror test with kvm on 1G image · db5e8210
      Vladimir Sementsov-Ogievskiy authored 
      

This test is broken without previous commit fixing dead-lock in mirror.
Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Acked-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
      db5e8210
    • Vladimir Sementsov-Ogievskiy's avatar
      mirror: fix dead-lock · d12ade57
      Vladimir Sementsov-Ogievskiy authored 
      Let start from the beginning:

Commit b9e413dd (in 2.9)
"block: explicitly acquire aiocontext in aio callbacks that need it"
added pairs of aio_context_acquire/release to mirror_write_complete and
mirror_read_complete, when they were aio callbacks for blk_aio_* calls.

Then, commit 2e1990b2

 (in 3.0) "block/mirror: Convert to coroutines"
dropped these blk_aio_* calls, than mirror_write_complete and
mirror_read_complete are not callbacks more, and don't need additional
aiocontext acquiring. Furthermore, mirror_read_complete calls
blk_co_pwritev inside these pair of aio_context_acquire/release, which
leads to the following dead-lock with mirror:

 (gdb) info thr
   Id   Target Id         Frame
   3    Thread (LWP 145412) "qemu-system-x86" syscall ()
   2    Thread (LWP 145416) "qemu-system-x86" __lll_lock_wait ()
 * 1    Thread (LWP 145411) "qemu-system-x86" __lll_lock_wait ()

 (gdb) bt
 #0  __lll_lock_wait ()
 #1  _L_lock_812 ()
 #2  __GI___pthread_mutex_lock
 #3  qemu_mutex_lock_impl (mutex=0x561032dce420 <qemu_global_mutex>,
     file=0x5610327d8654 "util/main-loop.c", line=236) at
     util/qemu-thread-posix.c:66
 #4  qemu_mutex_lock_iothread_impl
 #5  os_host_main_loop_wait (timeout=480116000) at util/main-loop.c:236
 #6  main_loop_wait (nonblocking=0) at util/main-loop.c:497
 #7  main_loop () at vl.c:1892
 #8  main

Printing contents of qemu_global_mutex, I see that "__owner = 145416",
so, thr1 is main loop, and now it wants BQL, which is owned by thr2.

 (gdb) thr 2
 (gdb) bt
 #0  __lll_lock_wait ()
 #1  _L_lock_870 ()
 #2  __GI___pthread_mutex_lock
 #3  qemu_mutex_lock_impl (mutex=0x561034d25dc0, ...
 #4  aio_context_acquire (ctx=0x561034d25d60)
 #5  dma_blk_cb
 #6  dma_blk_io
 #7  dma_blk_read
 #8  ide_dma_cb
 #9  bmdma_cmd_writeb
 #10 bmdma_write
 #11 memory_region_write_accessor
 #12 access_with_adjusted_size
 #15 flatview_write
 #16 address_space_write
 #17 address_space_rw
 #18 kvm_handle_io
 #19 kvm_cpu_exec
 #20 qemu_kvm_cpu_thread_fn
 #21 qemu_thread_start
 #22 start_thread
 #23 clone ()

Printing mutex in fr 2, I see "__owner = 145411", so thr2 wants aio
context mutex, which is owned by thr1. Classic dead-lock.

Then, let's check that aio context is hold by mirror coroutine: just
print coroutine stack of first tracked request in mirror job target:

 (gdb) [...]
 (gdb) qemu coroutine 0x561035dd0860
 #0  qemu_coroutine_switch
 #1  qemu_coroutine_yield
 #2  qemu_co_mutex_lock_slowpath
 #3  qemu_co_mutex_lock
 #4  qcow2_co_pwritev
 #5  bdrv_driver_pwritev
 #6  bdrv_aligned_pwritev
 #7  bdrv_co_pwritev
 #8  blk_co_pwritev
 #9  mirror_read_complete () at block/mirror.c:232
 #10 mirror_co_read () at block/mirror.c:370
 #11 coroutine_trampoline
 #12 __start_context

Yes it is mirror_read_complete calling blk_co_pwritev after acquiring
aio context.
Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
      d12ade57
    • Roman Bolshakov's avatar
      i386: hvf: Fix overrun of _decode_tbl1 · 83ea23cd
      Roman Bolshakov authored 
      

Single opcode instructions in ff group were incorrectly processed
because an overrun of _decode_tbl1[0xff] resulted in access of
_decode_tbl2[0x0]. Thus, decode_sldtgroup was called instead of
decode_ffgroup:
  7d71: decode_sldtgroup: 1
  Unimplemented handler (7d71) for 108 (ff 0)

While at it correct maximum length for _decode_tbl2 and _decode_tbl3.
Signed-off-by: default avatarRoman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
      83ea23cd
    • Corey Minyard's avatar
      i2c: Add a length check to the SMBus write handling · 629457a1
      Corey Minyard authored 
      

Avoid an overflow.
Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
Cc: QEMU Stable <qemu-stable@nongnu.org>
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
      629457a1
  3. 28 Nov, 2018 5 commits
  5. 27 Nov, 2018 27 commits
  7. 26 Nov, 2018 3 commits