The list seems to be guarded by a spin lock while adding items to the list. I don't see holding such a lock while removing list items. There is some code that goes through the list without any lock either. Most of it is single threaded, except the work queue thread (scsi_wq) and the unload thread when we unload the driver could race. It is quite possible that I just mis-understood this whole thing. Thanks, Malahal. James Bottomley [James.Bottomley@xxxxxxxxxxxx] wrote: > If someone is bored, they can take a look at this list debug error: > > list_add corruption. prev->next should be dfa0b788, but was f795fd50 > ------------[ cut here ]------------ > kernel BUG at lib/list_debug.c:31! > invalid opcode: 0000 [#1] > SMP > Modules linked in: aic94xx libsas firmware_class scsi_transport_sas sd_mod scsi_transport_spi scsi_mod > CPU: 0 > EIP: 0060:[<c01df32e>] Not tainted VLI > EFLAGS: 00010286 (2.6.18 #14) > EIP is at __list_add+0x6e/0x80 > eax: 00000048 ebx: dfa0b788 ecx: 00000003 edx: 00000008 > esi: f7929bb8 edi: dfaa2888 ebp: dfeabeec esp: dfeabed4 > ds: 007b es: 007b ss: 0068 > Process scsi_wq_0 (pid: 872, ti=dfeaa000 task=dfe60030 task.ti=dfeaa000) > Stack: c030a7b8 dfa0b788 f795fd50 dfa0b76c dfaa2864 00000000 dfeabf30 f884458d > dfaa2888 f7929bb8 dfa0b788 00000001 c0114da0 dfaefd24 dfa2c2f0 dfa088f4 > 00000286 dfa08ae4 dfa0b7ec dfaa2864 dfa0b6b8 dfa0b6bc dfaefd24 dfeabf64 > Call Trace: > [<f884458d>] sas_discover_domain+0x2ed/0x4c0 [libsas] > [<c012d3bf>] run_workqueue+0x7f/0x100 > [<c012dca8>] worker_thread+0x148/0x170 > [<c0130c2d>] kthread+0xfd/0x110 > [<c0103e33>] kernel_thread_helper+0x7/0x14 > ======================= > Code: 08 c7 04 24 78 a7 30 c0 e8 c0 e1 f3 ff 0f 0b 1a 00 77 a2 30 c0 eb c5 89 5c 24 04 89 44 24 08 c7 04 24 b8 a7 30 c0 e8 a2 e1 f3 ff <0f> 0b 1f 00 77 a2 30 c0 eb ad 90 8d b4 26 00 00 00 00 55 89 e5 > EIP: [<c01df32e>] __list_add+0x6e/0x80 SS:ESP 0068:dfeabed4 > > This seems to be coming from the > > list_add_tail(&dev->dev_list_node, &port->dev_list); > > in sas_get_port_device() > > James > > > - > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
