Dear list, I think I'm experiencing a race condition: Irregularly my kernel runs into an Oops when it tries to initialize my crypt containers.
> Mar 23 17:33:08 1A:hejre kernel: BUG: unable to handle kernel NULL pointer > dereference at virtual address 00000000 > Mar 23 17:33:08 1A:hejre kernel: printing eip: > Mar 23 17:33:08 4A:hejre kernel: c0143543 > Mar 23 17:33:08 1A:hejre kernel: *pde = 00000000 > Mar 23 17:33:08 0A:hejre kernel: Oops: 0000 [#1] > Mar 23 17:33:08 0A:hejre kernel: PREEMPT > Mar 23 17:33:08 4A:hejre kernel: Modules linked in: xt_NFQUEUE xt_tcpudp > xt_state xt_limit xt_CONNMARK xt_connmark xt_multiport ipt_REDIRECT > ipt_MASQUERADE ipt_LOG nfnetlink_queue nfnetlink iptable_mangle iptable_nat > nf_nat nf_conntrack_ipv4 nf_conntrack iptable_filter ip_tables x_tables ipv6 > xfrm4_mode_transport esp4 deflate des md5 crypto_null hmac crypto_hash af_key > ntfs sha256 aes_i586 cbc dm_crypt dm_mod snd_virmidi snd_seq_virmidi > snd_ca0106 snd_ac97_codec snd_pcm_oss snd_mixer_oss snd_pcm ac97_bus > snd_page_alloc snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi > snd_seq_midi_event snd_seq snd_timer snd_seq_device snd soundcore usb_storage > sd_mod scsi_mod nls_utf8 nls_cp850 nls_iso8859_1 hisax_fcpcipnp hisax_isac > hisax via686a w83781d hwmon_vid hwmon i2c_isa i2c_viapro i2c_core msr > isdn_bsdcomp isdn cpuid rtc > Mar 23 17:33:08 0A:hejre kernel: CPU: 0 > Mar 23 17:33:08 0A:hejre kernel: EIP: 0060:[<c0143543>] Not tainted VLI > Mar 23 17:33:08 0A:hejre kernel: EFLAGS: 00010282 (2.6.20-git12 #2) > Mar 23 17:33:08 0A:hejre kernel: EIP is at mempool_free+0x13/0xb0 > Mar 23 17:33:08 0A:hejre kernel: eax: cdf39d44 ebx: cdf39d44 ecx: > 00000001 edx: 00000000 > Mar 23 17:33:08 0A:hejre kernel: esi: 00000000 edi: cdf39d44 ebp: > dff19eb4 esp: dff19ea4 > Mar 23 17:33:08 0A:hejre kernel: ds: 007b es: 007b fs: 00d8 gs: 0000 > ss: 0068 > Mar 23 17:33:08 0A:hejre kernel: Process kcryptd/0 (pid: 772, ti=dff18000 > task=dff050d0 task.ti=dff18000) > Mar 23 17:33:08 0A:hejre kernel: Stack: c011c58b cdf39d44 00000000 dd87f9e0 > dff19ed8 e092c792 e092d7c4 cdf39d44 > Mar 23 17:33:08 0A:hejre kernel: e0a45040 dd87f9e0 dff19f20 dd87f9e0 > dfbb76e0 dff19f4c e092cc1b d10abbe0 > Mar 23 17:33:08 0A:hejre kernel: 0000007c 00000000 00000000 d10abbe0 > cdf39d44 d10ab9a0 c0117598 0000000f > Mar 23 17:33:08 0A:hejre kernel: Call Trace: > Mar 23 17:33:08 0A:hejre kernel: [<c010500a>] show_trace_log_lvl+0x1a/0x30 > Mar 23 17:33:08 0A:hejre kernel: [<c01050c9>] show_stack_log_lvl+0xa9/0xd0 > Mar 23 17:33:08 0A:hejre kernel: [<c01052d1>] show_registers+0x1e1/0x330 > Mar 23 17:33:08 0A:hejre kernel: [<c010552e>] die+0x10e/0x230 > Mar 23 17:33:08 0A:hejre kernel: [<c01168a0>] do_page_fault+0x2b0/0x5d0 > Mar 23 17:33:08 0A:hejre kernel: [<c0319bd4>] error_code+0x74/0x7c > Mar 23 17:33:08 0A:hejre kernel: [<e092c792>] dec_pending+0x62/0x80 > [dm_crypt] > Mar 23 17:33:08 0A:hejre kernel: [<e092cc1b>] kcryptd_do_work+0x2fb/0x3b0 > [dm_crypt] > Mar 23 17:33:08 0A:hejre kernel: [<c012b6e4>] run_workqueue+0xa4/0x180 > Mar 23 17:33:08 0A:hejre kernel: [<c012bde7>] worker_thread+0x137/0x160 > Mar 23 17:33:08 0A:hejre kernel: [<c012ec73>] kthread+0xa3/0xd0 > Mar 23 17:33:08 0A:hejre kernel: [<c0104c3b>] kernel_thread_helper+0x7/0x1c > Mar 23 17:33:08 0A:hejre kernel: ======================= > Mar 23 17:33:08 0A:hejre kernel: Code: f4 45 1d 00 8d 74 26 00 eb d3 31 db e9 > 37 ff ff ff 8d b4 26 00 00 00 00 55 89 e5 83 ec 10 89 75 f8 89 7d fc 89 d6 89 > 5d f4 89 c7 <8b> 02 39 42 04 7d 27 9c 5b fa 89 e0 25 00 e0 ff ff ff 40 14 8b > Mar 23 17:33:08 0A:hejre kernel: EIP: [<c0143543>] mempool_free+0x13/0xb0 > SS:ESP 0068:dff19ea4 The userland process triggering the BUG gets stuck in sync_page, but the rest of the system survives. - I suspected dec_pending's cc pointer to become invalid, so I inserted a few printk()s in crypt_ctr, _dtr and dec_pending, et voilà: (successful cryptsetup, a few days ago) > Mar 21 20:37:31 6A:hejre kernel: Crypt_Ctr, DmTarget e0a4c040 now has > CryptConfig daf12aa0. > Mar 21 20:37:31 4A:hejre kernel: This is dm_crypt::dec_pending, IO d4e03e84, > DmTgt e0a4c040, CC daf12aa0. > Mar 21 20:37:31 4A:hejre last message repeated 124 times > Mar 21 20:37:31 6A:hejre kernel: Crypt_Dtr, freeing DmTarget e0a4c040's > CryptConfig daf12aa0. > Mar 21 20:37:31 6A:hejre kernel: Crypt_Ctr, DmTarget e0a4c040 now has > CryptConfig daf12ba0. > Mar 21 20:37:31 4A:hejre kernel: This is dm_crypt::dec_pending, IO d4e03e84, > DmTgt e0a4c040, CC daf12ba0. > Mar 21 20:37:31 4A:hejre kernel: This is dm_crypt::dec_pending, IO d4e03e5c, > DmTgt e0a4c040, CC daf12ba0. > Mar 21 20:37:31 4A:hejre kernel: This is dm_crypt::dec_pending, IO d4e03e34, > DmTgt e0a4c040, CC daf12ba0. > [... and continues happily] (context of the above oops) > Mar 23 17:33:08 6A:hejre kernel: Crypt_Ctr, DmTarget e0a45040 now has > CryptConfig dd87f9e0. > Mar 23 17:33:08 4A:hejre kernel: This is dm_crypt::dec_pending, IO cdf39d44, > DmTgt e0a45040, CC dd87f9e0. > Mar 23 17:33:08 4A:hejre kernel: This is dm_crypt::dec_pending, IO cdf39d1c, > DmTgt e0a45040, CC dd87f9e0. > [some more of those] > Mar 23 17:33:08 4A:hejre kernel: This is dm_crypt::dec_pending, IO cdf39d1c, > DmTgt e0a45040, CC dd87f9e0. > Mar 23 17:33:08 4A:hejre kernel: This is dm_crypt::dec_pending, IO cdf39d44, > DmTgt e0a45040, CC dd87f9e0. > Mar 23 17:33:08 6A:hejre kernel: Crypt_Dtr, freeing DmTarget e0a45040's > CryptConfig dd87f9e0. > Mar 23 17:33:08 1A:hejre kernel: BUG: unable to handle kernel NULL pointer > dereference at virtual address 00000000 > Mar 23 17:33:08 1A:hejre kernel: printing eip: > [...] > Mar 23 17:33:08 0A:hejre kernel: EIP: [<c0143543>] mempool_free+0x13/0xb0 > SS:ESP 0068:dff19ea4 > Mar 23 17:33:08 6A:hejre kernel: Crypt_Ctr, DmTarget e0a45040 now has > CryptConfig dd87fce0. I'm seeing this for quite a while now (since 2.6.16 at least), but without any obvious indicator to what might be causing it... where should I continue debugging this? Thanks in advance, Jan Nordholz - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
