Merge branch 'ena-bug-fixes' - net-next.git

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author	David S. Miller <davem@davemloft.net>	2017-02-09 22:27:08 -0500
committer	David S. Miller <davem@davemloft.net>	2017-02-09 22:27:08 -0500
commit	9878f60240f786286ebfaa8ff9227ef38da1720c (patch)
tree	b39c6b130ae03f217307f2cd3eb5e7659514a5e4 /sound/last.c
parent	b66a8043d0baa9818a407ed857eada5cb21cd9bb (diff)
parent	3e5d6897176d38b54124da56183810abbd68c8bc (diff)

Merge branch 'ena-bug-fixes'

Netanel Belgazal says: ==================== Bug Fixes in ENA driver Changes from V3: * Rebase patchset to master and solve merge conflicts. * Remove redundant bug fix (fix error handling when probe fails) ==================== Signed-off-by: David S. Miller <davem@davemloft.net>

Diffstat (limited to 'sound/last.c')

0 files changed, 0 insertions, 0 deletions

, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+

Diffstat (limited to 'tools/perf/python/twatch.py')


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