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由 Stephen M. Cameron 提交于
If a new logical drive is added and the CCISS_REGNEWD ioctl is invoked (as is normal with the Array Configuration Utility) the process will hang as below. It attempts to acquire the same mutex twice, once in do_ioctl() and once in cciss_unlocked_open(). The BKL was recursive, the mutex isn't. Linux version 3.10.0-rc2 (scameron@localhost.localdomain) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-3) (GCC) ) #1 SMP Fri May 24 14:32:12 CDT 2013 [...] acu D 0000000000000001 0 3246 3191 0x00000080 Call Trace: schedule+0x29/0x70 schedule_preempt_disabled+0xe/0x10 __mutex_lock_slowpath+0x17b/0x220 mutex_lock+0x2b/0x50 cciss_unlocked_open+0x2f/0x110 [cciss] __blkdev_get+0xd3/0x470 blkdev_get+0x5c/0x1e0 register_disk+0x182/0x1a0 add_disk+0x17c/0x310 cciss_add_disk+0x13a/0x170 [cciss] cciss_update_drive_info+0x39b/0x480 [cciss] rebuild_lun_table+0x258/0x370 [cciss] cciss_ioctl+0x34f/0x470 [cciss] do_ioctl+0x49/0x70 [cciss] __blkdev_driver_ioctl+0x28/0x30 blkdev_ioctl+0x200/0x7b0 block_ioctl+0x3c/0x40 do_vfs_ioctl+0x89/0x350 SyS_ioctl+0xa1/0xb0 system_call_fastpath+0x16/0x1b This mutex usage was added into the ioctl path when the big kernel lock was removed. As it turns out, these paths are all thread safe anyway (or can easily be made so) and we don't want ioctl() to be single threaded in any case. Signed-off-by: NStephen M. Cameron <scameron@beardog.cce.hp.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mike Miller <mike.miller@hp.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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