Date: Fri, 29 Jul 2005 09:20:34 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: Frank McConnell <fmc@reanimators.org> Cc: freebsd-stable@freebsd.org Subject: Re: RELENG_5 PAE panic Message-ID: <20050729091624.R74149@fledge.watson.org> In-Reply-To: <200507290034.j6T0YLdZ014411@lots.reanimators.org> References: <200507290034.j6T0YLdZ014411@lots.reanimators.org>
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On Thu, 28 Jul 2005, Frank McConnell wrote: > --- begin paste --- > Fatal trap 12: page fault while in kernel mode > fault virtual address = 0x24 > fault code = supervisor read, page not present > instruction pointer = 0x8:0xc03db1cf > stack pointer = 0x10:0xeb328c64 > frame pointer = 0x10:0xeb328c78 > code segment = base 0x0, limit 0xfffff, type 0x1b > = DPL 0, pres 1, def32 1, gran 1 > processor eflags = resume, IOPL = 0 > current process = 70 (pagedaemon) > [thread pid 70 tid 100080 ] > Stopped at 0xc03db1cf = propagate_priority+0x7f: movl 0x24(%eax),%eax > db> trace > Tracing pid 70 tid 100080 td 0xc6a89000 > propagate_priority(c6a89000,c0628280,c0636c60,c6a89000,c6cdaa82) at 0xc03db1cf = propagate_priority+0x7f > turnstile_wait(c6a6f240,c0636c60,c6cdaa80) at 0xc03db84a = turnstile_wait + 0x266 > _mtx_lock_sleep(c0636c60,c6a89000,0,0,0) at 0xc03b4c25 = _mtx_lock_speed+0xad > msleep(c0637104,c0636c60,44,c059aa74,1f4) at 0xc03c37ea = msleep+0x39a > vm_pageout(0,eb328d38) at 0xc04fb0e4 = vm_pageout+0x280 > fork_exit(c04fae64,0,eb328d38) at 0xc03a8680 = fork_exit+0x74 > fork_trampoline() at 0xc0539d9c = fork_trampoline+0x8 > --- trap 0x1, eip = 0, esp = 0xeb328d6c, ebp = 0 --- > db> This appears to be a NULL pointer dereference in propagate_priotity(). Often a panic in propagate_priority is actually a symptom of a slightly earlier problem which is discovered by propagate_priority when it trips over, for example, a bad mutex. If you're set up with a serial port to copy and paste debugging output, the output of 'ps' and 'show pcpu' for each of the cpus (as well as 'show pcpu without a cpu argument) would be helpful. It wouldn't hurt also to use gdb on a copy of the kernel with debugging sybols to map 'vm_pageout+0x280' into a line number. Details on these various activities can be found in the handbook. Robert N M Watson
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