Date: Fri, 23 Mar 2018 10:49:33 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 226870] [panic] cdstrategy violates GEOM I/O contract Message-ID: <bug-226870-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=226870 Bug ID: 226870 Summary: [panic] cdstrategy violates GEOM I/O contract Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: avg@FreeBSD.org anic: sleepq_add: td 0xfffff80008e1c000 to sleep on wchan 0xfffff801e58b8048 with sleeping prohibited cpuid = 0 curthread: 0xfffff80008e1c000 stack: 0xfffffe07e1883000 - 0xfffffe07e1887000 stack pointer: 0xfffffe07e1886820 time = 1521652565 KDB: stack backtrace: db_trace_self_wrapper() at 0xffffffff804670bb = db_trace_self_wrapper+0x2b/frame 0xfffffe07e1886750 kdb_backtrace() at 0xffffffff806d4c79 = kdb_backtrace+0x39/frame 0xfffffe07e1886800 vpanic() at 0xffffffff80699da6 = vpanic+0x166/frame 0xfffffe07e1886840 kassert_panic() at 0xffffffff80699adb = kassert_panic+0x16b/frame 0xfffffe07e18868b0 sleepq_add() at 0xffffffff806e1902 = sleepq_add+0x342/frame 0xfffffe07e1886910 _sleep() at 0xffffffff806a41f7 = _sleep+0x2b7/frame 0xfffffe07e18869b0 cam_periph_ccbwait() at 0xffffffff802b53ad = cam_periph_ccbwait+0x5d/frame 0xfffffe07e18869e0 cam_periph_runccb() at 0xffffffff802b51d8 = cam_periph_runccb+0xb8/frame 0xfffffe07e1886a40 cdrunccb() at 0xffffffff802d52fc = cdrunccb+0x3c/frame 0xfffffe07e1886a60 cdprevent() at 0xffffffff802d4beb = cdprevent+0x7b/frame 0xfffffe07e1886aa0 cdcheckmedia() at 0xffffffff802d48b2 = cdcheckmedia+0x22/frame 0xfffffe07e1886af0 cdstrategy() at 0xffffffff802d2a36 = cdstrategy+0x56/frame 0xfffffe07e1886b20 g_disk_start() at 0xffffffff80608330 = g_disk_start+0x170/frame 0xfffffe07e1886b70 g_io_schedule_down() at 0xffffffff8060c1db = g_io_schedule_down+0x1eb/frame 0xfffffe07e1886b90 g_down_procbody() at 0xffffffff8060cbdd = g_down_procbody+0x6d/frame 0xfffffe07e1886ba0 fork_exit() at 0xffffffff8065e410 = fork_exit+0xd0/frame 0xfffffe07e1886bf0 fork_trampoline() at 0xffffffff808e4aee = fork_trampoline+0xe/frame 0xfffffe07e1886bf0 The cause is obvious. There must no sleeping in the GEOM I/O threads (up and down). But cdstrategy may violate this contract if it detects that a disk has been removed. In this case it calls cdcheckmedia() that closes the CD-ROM tray, locks it and tastes the disk (if present). These are all blocking operations and can potentially take a long time since mechanical actions are involved. I am not sure how to fix this. A naive approach is to just fail the request when the CD-ROM is without media (including when its tray is open). -- You are receiving this mail because: You are the assignee for the bug.
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