Re: [Bug 739] New: Null pointer dereference in

Alex Tomas (bzzz@tmi.comex.ru)
Thu, 22 May 2003 23:46:17 +0000


I think we already know the reason. Fix will be available soon.

>>>>> Martin J Bligh (MJB) writes:

MJB> Summary: Null pointer dereference in ext3_test_allocatable
MJB> Kernel Version: 2.5.69-mm8
MJB> Status: NEW
MJB> Severity: normal
MJB> Owner: akpm@digeo.com
MJB> Submitter: plars@austin.ibm.com

MJB> Distribution: RH7.3
MJB> Hardware Environment: 8-way PIII-700, 16 GB ram

MJB> Software Environment:
MJB> anticipatory scheduler, ext3, preempt enabled

MJB> Problem Description:
MJB> While I was trying to reproduce bug 738, I got this but I believe it is
MJB> sufficiently different enough to call it a new bug. Apologies in advance if I'm
MJB> wrong on that. I was also able to produce this one earlier today when I was
MJB> compiling LTP but was unsuccessful upon trying it again. I didn't have the
MJB> serial console setup during the LTP compile when I produced this bug the first
MJB> time so I missed the output that time, but I recognize the Null pointer and the
MJB> EIP from before.

MJB> Unable to handle kernel NULL pointer dereference at virtual address 00000010
MJB> printing eip:
MJB> c0197db3
MJB> *pde = 35b80001
MJB> Oops: 0000 [#1]
MJB> CPU: 3
MJB> EIP: 0060:[<c0197db3>] Not tainted VLI
MJB> EFLAGS: 00010206
MJB> EIP is at ext3_test_allocatable+0x23/0x40
MJB> eax: 00000000 ebx: f6a9e000 ecx: 00002c76 edx: f6628688
MJB> esi: 00002c76 edi: 00002c60 ebp: 00000000 esp: f6b11a2c
MJB> ds: 007b es: 007b ss: 0068
MJB> Process ftest07 (pid: 1354, threadinfo=f6b10000 task=f63a3920)
MJB> Stack: c0197f9f 00002c76 f6628688 00000000 00001000 f6a9e000 00008000 ffffffff
MJB> f7c6351c f6628688 c01980d6 ffffffff f6628688 00008000 00000000 c0160744
MJB> f7c5c6dc 001c0000 00001000 00000037 00000038 f7c6351c f6b11ac8 c019848d
MJB> Call Trace:
MJB> [<c0197f9f>] find_next_usable_block+0x1cf/0x2c0
MJB> [<c01980d6>] ext3_try_to_allocate+0x46/0x190
MJB> [<c0160744>] __bread+0x14/0x30
MJB> [<c019848d>] ext3_new_block+0x26d/0x610
MJB> [<c011cbb6>] __wake_up+0x66/0xb0
MJB> [<c019a9cd>] ext3_alloc_block+0x1d/0x30
MJB> [<c019ad45>] ext3_alloc_branch+0x45/0x280
MJB> [<c01605fa>] bh_lru_install+0xca/0xf0
MJB> [<c019b31f>] ext3_get_block_handle+0x20f/0x2f0
MJB> [<c0162b43>] alloc_buffer_head+0x13/0x60
MJB> [<c015ff87>] create_buffers+0x57/0xb0
MJB> [<c019b460>] ext3_get_block+0x60/0x70
MJB> [<c0161070>] __block_prepare_write+0x140/0x3e0
MJB> [<c010829c>] __up_wakeup+0x8/0xc
MJB> [<c0161bf0>] block_prepare_write+0x20/0x40
MJB> [<c019b400>] ext3_get_block+0x0/0x70
MJB> [<c019b882>] ext3_prepare_write+0x42/0xe0
MJB> [<c019b400>] ext3_get_block+0x0/0x70
MJB> [<c013e12e>] generic_file_aio_write_nolock+0x66e/0xac0
MJB> [<c013bb9a>] unlock_page+0xa/0x50
MJB> [<c013c994>] file_read_actor+0x64/0xd0
MJB> [<c013c9a1>] file_read_actor+0x71/0xd0
MJB> [<c013c535>] do_generic_mapping_read+0xf5/0x4f0
MJB> [<c0179a2d>] update_atime+0x6d/0xc0
MJB> [<c013cbb5>] __generic_file_aio_read+0x1b5/0x1e0
MJB> [<c013e619>] generic_file_write_nolock+0x99/0xc0
MJB> [<c0160dc4>] __block_write_full_page+0x284/0x3f0
MJB> [<c011f7c0>] autoremove_wake_function+0x0/0x40
MJB> [<c011f7c0>] autoremove_wake_function+0x0/0x40
MJB> [<c0182174>] mpage_writepages+0x234/0x3d0
MJB> [<c01657c0>] blkdev_writepage+0x0/0x20
MJB> [<c0142b89>] check_poison_obj+0x39/0x190
MJB> [<c0144a5a>] kmalloc+0xfa/0x1c0
MJB> [<c013e850>] generic_file_writev+0x40/0x60
MJB> [<c015dc30>] do_readv_writev+0x1c0/0x270
MJB> [<c015d6d0>] do_sync_write+0x0/0xe0
MJB> [<c015d07d>] generic_file_llseek+0x2d/0xd0
MJB> [<c015d050>] generic_file_llseek+0x0/0xd0
MJB> [<c015dd77>] vfs_writev+0x47/0x50
MJB> [<c015ddff>] sys_writev+0x2f/0x50
MJB> [<c01094df>] syscall_call+0x7/0xb

MJB> Code: 00 8d bc 27 00 00 00 00 8b 54 24 08 8b 4c 24 04 8b 42 18 0f a3 08 19 c0 85
MJB> c0 74 03 31 c0 c3 8b 02 a9 00 04 00 00 74 0a 8b 42 24 <8b> 40 10 85 c0 75 06 b8
MJB> 01 00 00 00 c3 0f a3 08 19 d2 31 c0 85

MJB> Steps to reproduce:
MJB> from a current CVS of LTP (today is 5/22/2003):
MJB> run ftest07 in one session
MJB> while waiting for that to complete (it takes a while)
MJB> I ran these:
MJB> aio01 -n100000
MJB> aio01 -c10 -n10000

MJB> Both completed successfully but when ftest07 finished it had the output above.

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