Re: BUG on 2.6.20-rc1 when using gdb

Andrew Morton
2006-12-20T00:42:28Z

On Sun, 17 Dec 2006 20:55:18 -0500
"Andrew J. Barr" <andrew.james.barr@gmail.com> wrote:

> When I was using gdb to debug xchat-gnome, I got a kernel BUG and stack
> trace as the program was running (e.g. I had typed 'run' in gdb):
>
> WARNING at kernel/softirq.c:137 local_bh_enable()
> [<c0103cd6>] dump_trace+0x68/0x1d9
> [<c0103e5f>] show_trace_log_lvl+0x18/0x2c
> [<c01044d3>] show_trace+0xf/0x11
> [<c010455e>] dump_stack+0x12/0x14
> [<c011cc7d>] local_bh_enable+0x44/0x94
> [<c02871b9>] unix_release_sock+0x6e/0x1fe
> [<c02887eb>] unix_stream_connect+0x3b4/0x3cf
> [<c0232dee>] sys_connect+0x82/0xad
> [<c0233641>] sys_socketcall+0xac/0x261
> [<c0102d38>] syscall_call+0x7/0xb
> [<b7f70822>] 0xb7f70822
> =======================
> ------------[ cut here ]------------
> kernel BUG at fs/buffer.c:1235!
> invalid opcode: 0000 [#1]
> PREEMPT
> Modules linked in: binfmt_misc rfcomm l2cap i915 drm bluetooth nfs nfsd
> exportfs lockd nfs_acl sunrpc nvram uinput ipv6 ppdev lp button ac
> battery dm_crypt dm_snapshot dm_mirror dm_mod fuse cpufreq_conservative
> cpufreq_ondemand cpufreq_performance cpufreq_powersave
> speedstep_centrino freq_table ibm_acpi loop snd_intel8x0m snd_pcm_oss
> snd_mixer_oss snd_intel8x0 snd_ac97_codec pcmcia ac97_bus irtty_sir
> sir_dev ipw2200 snd_pcm snd_timer irda ieee80211 ieee80211_crypt
> crc_ccitt rtc parport_pc parport 8250_pnp snd soundcore 8250_pci 8250
> serial_core firmware_class i2c_i801 yenta_socket rsrc_nonstatic
> pcmcia_core snd_page_alloc i2c_core intel_agp agpgart evdev tsdev joydev
> ext3 jbd mbcache ide_cd cdrom ide_disk ide_generic e100 mii generic piix
> ide_core ehci_hcd uhci_hcd usbcore
> CPU: 0
> EIP: 0060:[<c0179266>] Not tainted VLI
> EFLAGS: 00010046 (2.6.20-rc1 #1)
> EIP is at __find_get_block+0x1c/0x16f
> eax: 00000086 ebx: 00000000 ecx: 00000000 edx: 0088a800
> esi: 0088a800 edi: 00000000 ebp: dfffd040 esp: cad2dd30
> ds: 007b es: 007b ss: 0068
> Process xchat-gnome (pid: 4322, ti=cad2c000 task=d0cd3ab0
> task.ti=cad2c000)
> Stack: cad2dd58 c02caa0b 00000002 0000000e 0000000b 00000001 e8836580
> 0088a800
> 00000000 00000000 e8836610 00000000 c01793dc 00001000 c03ab3e0
> f3cadd80
> 00000086 c90d41b0 0088a800 00000000 dfffd040 00008000 00000000
> 00000002
> Call Trace:
> [<c01793dc>] __getblk+0x23/0x268
> [<f040d4c6>] ext3_getblk+0x10b/0x244 [ext3]
> [<f040e364>] ext3_bread+0x19/0x70 [ext3]
> [<f04106f3>] dx_probe+0x43/0x2c9 [ext3]
> [<f04119b3>] ext3_htree_fill_tree+0x99/0x1ba [ext3]
> [<f040ab77>] ext3_readdir+0x1d4/0x5ed [ext3]
> [<c0167b29>] vfs_readdir+0x63/0x8d
> [<c0167bb6>] sys_getdents64+0x63/0xa5
> [<c0102d38>] syscall_call+0x7/0xb
> [<b7f70822>] 0xb7f70822
> =======================
> Code: 8b 40 08 a8 08 74 05 e8 02 2f 11 00 5b 5e c3 55 89 c5 57 89 cf 56
> 89 d6 53 83 ec 20 9c 58 90 8d b4 26 00 00 00 00 f6 c4 02 75 04 <0f> 0b
> eb fe 89 e0 25 00 e0 ff ff ff 40 14 31 c9 8b 1c 8d a0 74
> EIP: [<c0179266>] __find_get_block+0x1c/0x16f SS:ESP 0068:cad2dd30
>
> This happens on 2.6.20-rc1 but not 2.6.19.
>

And it's repeatable, yes?

And you're sure that use of gdb triggers it?

Something is forgetting to reenable local interrupts.