Date: Sat, 22 Dec 2012 13:21:24 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Andriy Gapon <avg@freebsd.org> Cc: Garrett Cooper <yanegomi@gmail.com>, freebsd-net@freebsd.org, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: Fatal trap 1 [Was: "Memory modified after free" - by whom?] Message-ID: <20121222112124.GN53644@kib.kiev.ua> In-Reply-To: <50D5949A.1060505@FreeBSD.org> References: <CAGH67wQKUDLQmL8cnWwgzQpWAN2OhKLu0AemPNuy7EOC-i1p9g@mail.gmail.com> <CAJ-Vmo=MsSV3DhAVEP36d%2BFccHDdQz7%2By7v5xTjYKyBP0PfQoQ@mail.gmail.com> <CAMBSHm96ZEiF4mOhUyk-aDS%2BGs%2BhDsh_dMsd-WFcmZ%2BSm6Zk%2BA@mail.gmail.com> <CAGH67wQ8L5R8H7G7s%2B6b%2BiKaAz54es8scnASUQ8Env10x1iqzg@mail.gmail.com> <50D5949A.1060505@FreeBSD.org>
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[-- Attachment #1 --] On Sat, Dec 22, 2012 at 01:08:10PM +0200, Andriy Gapon wrote: > on 22/12/2012 02:21 Garrett Cooper said the following: > > Fatal trap 1: privileged instruction fault while in kernel mode > > Fatal trap 1: privileged instruction fault while in kernel mode > > Unrelated to the original topic - this looks very weird. > I mean all the CPUs getting this unusual trap... > Could you please do 'disassemble 0xffffffff80af5099' in kgdb with the same > kernel. Or if you have a different kernel now, please use "instruction pointer" > value from a trap with that kernel. > This is due to the vtoslab() returning NULL. Since slabref is dereferenced later, clang tries to be helpful as usual and converts the !(p->flags & PG_SLAB) case from vtoslab() into the jump to un2 instruction if vtoslab() result is NULL. So instead of KASSERT triggering the next line, you see this improvement. > > Memory modified after free 0xffffff800040d000(9216) val=5a5a5a5a @ > > 0xffffff800040d000 > > Fatal trap 1: privileged instruction fault while in kernel mode > > cpuid = 3; > > cpuid = 1; > > apic id = 02 > > cpuid = 0; apic id = 06 > > apic id = 00 > > instruction pointer = 0x20:0xffffffff80af5099 > > instruction pointer = 0x20:0xffffffff80af5099 > > instruction pointer = 0x20:0xffffffff80af5099 > > Fatal trap 1: privileged instruction fault while in kernel mode > > stack pointer = 0x28:0xffffff8496fff880 > > stack pointer = 0x28:0xffffff8496fe1880 > > cpuid = 2; frame pointer = 0x28:0xffffff8496fff8b0 > > frame pointer = 0x28:0xffffff8496fe18b0 > > stack pointer = 0x28:0xffffff849705d880 > > code segment = base 0x0, limit 0xfffff, type 0x1b > > frame pointer = 0x28:0xffffff849705d8b0 > > apic id = 04 > > code segment = base 0x0, limit 0xfffff, type 0x1b > > code segment = base 0x0, limit 0xfffff, type 0x1b > > = DPL 0, pres 1, long 1, def32 0, gran 1 > > = DPL 0, pres 1, long 1, def32 0, gran 1 > > instruction pointer = 0x20:0xffffffff80af5099 > > processor eflags = = DPL 0, pres 1, long > > 1, def32 0, gran 1 > > interrupt enabled, processor eflags = stack pointer = > > 0x28:0xffffff8497067880 > > interrupt enabled, resume, resume, frame pointer = > > 0x28:0xffffff84970678b0 > > IOPL = 0 > > code segment = base 0x0, limit 0xfffff, type 0x1b > > current process = = DPL 0, pres 1, long > > 1, def32 0, gran 1 > > processor eflags = 12 (irq280: ix0:que 3) > > ilock order reversal: (Giant after non-sleepable) > > 1st 0xfffffe0078148b38 ix0:rx(3) (ix0:rx(3)) @ > > /usr/src/sys/modules/ixgbe/../../dev/ixgbe/ixgbe.c:4296 > > 2nd 0xffffffff814457b8 Giant (Giant) @ /usr/src/sys/dev/usb/input/ukbd.c:1946 > > KDB: stack backtrace: > > db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xffffff8496fff320 > > kdb_backtrace() at kdb_backtrace+0x39/frame 0xffffff8496fff3d0 > > witness_checkorder() at witness_checkorder+0xc47/frame 0xffffff8496fff450 > > __mtx_lock_flags() at __mtx_lock_flags+0x89/frame 0xffffff8496fff490 > > ukbd_poll() at ukbd_poll+0x28/frame 0xffffff8496fff4b0 > > kbdmux_poll() at kbdmux_poll+0x5b/frame 0xffffff8496fff4d0 > > cngrab() at cngrab+0x35/frame 0xffffff8496fff4f0 > > kdb_trap() at kdb_trap+0x124/frame 0xffffff8496fff550 > > trap_fatal() at trap_fatal+0x345/frame 0xffffff8496fff5b0 > > trap() at trap+0x836/frame 0xffffff8496fff7c0 > > calltrap() at calltrap+0x8/frame 0xffffff8496fff7c0 > > --- trap 0x1, rip = 0xffffffff80af5099, rsp = 0xffffff8496fff880, rbp > > = 0xffffff8496fff8b0 --- > > uma_find_refcnt() at uma_find_refcnt+0x79/frame 0xffffff8496fff8b0 > > > -- > Andriy Gapon > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlDVl7QACgkQC3+MBN1Mb4i/AACcDPDRTKUrOx+7sGBKr/uDvlWe guAAnAkEl1FAAovlA4oWmJZKvjbHSVs2 =0QM1 -----END PGP SIGNATURE-----help
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