On Wed, Apr 08, 2015 at 06:33:33PM +0200, Torsten Luettgert wrote: > Hello, > > I'm getting NULL pointer deref BUGs on a Supermicro machine of > mine since 3.17. It occurs at random uptimes, often a few hours > after booting (max uptime was 2 days yet). > > I bisected the problem (took a while); the problematic commit seems > to be 746650160866 (scsi: convert host_busy to atomic_t) by > Christoph Hellwig. Seems like a very unlikely commit for this sort of change, so let's try to dig a bit deeper. > Here's one of the logs (it's always the same trace): > > BUG: unable to handle kernel NULL pointer dereference at > 0000000000000010 IP: [<ffffffff8133af60>] > swiotlb_unmap_sg_attrs+0x30/0x80 PGD 0 > Oops: 0000 [#1] SMP > Modules linked in: iTCO_wdt iTCO_vendor_support lpc_ich mfd_core > usb_storage CPU: 0 PID: 0 Comm: swapper/0 Not tainted > 3.16.0-74665016086615bb+ #1 Hardware name: Supermicro X8DTT/X8DTT, BIOS > 080016 10/05/2010 task: ffffffff81c16480 ti: ffffffff81c00000 task.ti: > ffffffff81c00000 RIP: 0010:[<ffffffff8133af60>] [<ffffffff8133af60>] > swiotlb_unmap_sg_attrs+0x30/0x80 RSP: 0018:ffff88063fc03e08 EFLAGS: > 00010002 RAX: 0000000000000000 RBX: 0000000000000001 RCX: > 0000000000000002 RDX: 0000000000000000 RSI: 000000090e2ef000 RDI: > ffff880c14e61a00 RBP: ffff88063fc03e38 R08: 0000000000000000 R09: > ffff8806209cc098 R10: ffff88063f400120 R11: 0000000000001268 R12: > 0000000000000002 R13: 0000000000000002 R14: ffff8806209cc098 R15: > ffff880c200fcc70 FS: 0000000000000000(0000) GS:ffff88063fc00000(0000) > knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > CR2: 0000000000000010 CR3: 0000000001c11000 CR4: 00000000000027e0 > Stack: > 0000000000000094 0000000000000094 ffff880c200f8718 0000000000000094 > 0000000000000094 0000000000000094 ffff88063fc03e48 ffffffff8146a0b4 > ffff88063fc03e88 ffffffff81477c1d ffff88063fc03e78 ffff880c213a57c0 > Call Trace: > <IRQ> > [<ffffffff8146a0b4>] scsi_dma_unmap+0x54/0x70 Can you run gdb on your vmlinux file and send the output of the following command in gdb l *(scsi_dma_unmap+0x54) Thanks! -- 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
