netsniff-ng.git - A high-performance Linux networking toolkit

Age	Commit message (Expand)	Author	Files	Lines
2015-01-12	gitignore: Add compiled executables	Vadim Kochan	1	-0/+11
2014-09-03	build: Add continuous integration support via travis-ci	Tobias Klauser	1	-0/+1
2013-07-12	gitignore: add config.log file to git ignore	Daniel Borkmann	1	-0/+1
2013-07-09	configure: let configure script generate config.h file	Daniel Borkmann	1	-0/+1
2013-06-24	gitignore: Ignore generated Config	Tobias Klauser	1	-0/+3
2013-05-21	misc: Ignore files generated by cscope/ctags	Tobias Klauser	1	-0/+4
2013-05-05	misc: move file to source root	Daniel Borkmann	1	-1/+1
2013-03-15	build: add make release target	Daniel Borkmann	1	-0/+3
2013-03-15	all: import netsniff-ng 0.5.8-rc0 source	Daniel Borkmann	1	-0/+42

_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, 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 'include/xen/interface/memory.h')