From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 11 May 2008 23:23:44 -0700 From: Andrew Morton Subject: Re: BUG: 2.6.26-rc1-git8: NULL reference in drop_buffers Message-Id: <20080511232344.b173ca9f.akpm@linux-foundation.org> In-Reply-To: <20080511105429.a5e40721.randy.dunlap@oracle.com> References: <20080511105429.a5e40721.randy.dunlap@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Randy Dunlap Cc: lkml , viro , Jan Kara , linux-mm@kvack.org List-ID: On Sun, 11 May 2008 10:54:29 -0700 Randy Dunlap wrote: > On x86_64, during testing using "stress" package: > > BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 > IP: [] drop_buffers+0x2f/0xfb > PGD 1ee8ad067 PUD 26f19a067 PMD 0 > Oops: 0000 [1] SMP > CPU 3 > Modules linked in: parport_pc lp parport tg3 cciss ehci_hcd ohci_hcd uhci_hcd > Pid: 16860, comm: stress Not tainted 2.6.26-rc1-git8 #1 > RIP: 0010:[] [] drop_buffers+0x2f/0xfb > RSP: 0000:ffff81026bc03a08 EFLAGS: 00010203 > RAX: 0000000000000000 RBX: ffffe20008bae680 RCX: ffff81027f490f00 > RDX: 0000000000000000 RSI: ffff81026bc03a58 RDI: ffffe20008bae680 > RBP: ffff81026bc03a38 R08: ffff81026bc03b78 R09: ffff810001103780 > R10: ffff81026bc03a08 R11: ffff81026bc03c88 R12: ffffe20008bae680 > R13: ffff81027c412850 R14: ffff81026bc03d58 R15: ffff81026bc03a58 > FS: 00007fa9e7e416f0(0000) GS:ffff81027f806980(0000) knlGS:00000000f7f856c0 > CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > CR2: 0000000000000000 CR3: 000000027f973000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process stress (pid: 16860, threadinfo ffff81026bc02000, task ffff81027e424c50) > Stack: ffffe20008bafa68 ffffe20008bae680 ffff81027f490f00 ffff81026bc03a58 > ffff81026bc03d58 ffff81026bc03c88 ffff81026bc03a78 ffffffff802ad39f > ffff81027f490f00 ffffe20008b14060 0000000000000000 ffff81027f490f00 > Call Trace: > [] try_to_free_buffers+0x60/0xa2 > [] try_to_release_page+0x3b/0x41 > [] shrink_page_list+0x457/0x562 > [] shrink_inactive_list+0x126/0x361 > [] shrink_zone+0xe5/0x10a > [] try_to_free_pages+0x1ef/0x326 > [] ? isolate_pages_global+0x0/0x34 > [] __alloc_pages_internal+0x25a/0x3ad > [] __alloc_pages+0xb/0xd > [] handle_mm_fault+0x238/0x6d0 > [] do_page_fault+0x438/0x7de > [] error_exit+0x0/0x51 > > > Code: 41 57 49 89 f7 41 56 41 55 41 54 49 89 fc 53 48 83 ec 08 48 8b 07 25 00 08 00 00 48 85 c0 75 04 0f 0b eb fe 4c 8b 6f 10 4c 89 ea <48> 8b 02 25 00 08 00 00 48 85 c0 74 10 49 8b 44 24 18 48 85 c0 > RIP [] drop_buffers+0x2f/0xfb > RSP > CR2: 0000000000000000 > Kernel panic - not syncing: Fatal exception Seems that local variable `bh' is NULL. I wonder what the heck we did to cause that. Which filesystems were in use? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org