Re: kernel BUG at /build/buildd/linux-2.6.35/mm/filemap.c:128!

From: Robert ÅwiÄcki
Date: Fri Jan 07 2011 - 08:02:40 EST


but will be happy if someone else beats me to it.
>>
>> I have since found an omission in the restart_addr logic: looking back
>> at the October 2004 history of vm_truncate_count, I see that originally
>> I designed it to work one way, but hurriedly added a 7/6 redesign when
>> vma splitting turned out to leave an ambiguity. ÂI should have updated
>> the protection in mremap move at that time, but missed it.
>>
>> Robert, please try out the patch below (should apply fine to 2.6.35):
>
> In the beginning Âof Jan (3-4) at earliest I'm afraid, i.e. when I
> manage to get to my console-over-rs232 setup.

I cannot reproduce it even with the unpatched kernel, cause I get the
following oops (3 times out of 3 tries) relatively quickly. Still
trying.

Entering kdb (current=0xffff88006b525ac0, pid 12468) on processor 1 Oops: (null)
due to oops @ 0xffffffff810c2a1b
CPU 1 <c>
<d>Pid: 12468, comm: iknowthis Not tainted 2.6.37-rc2 #1
0GH911/Precision WorkStation 390
<d>RIP: 0010:[<ffffffff810c2a1b>] [<ffffffff810c2a1b>] next_pidmap+0x4b/0xa0
<d>RSP: 0000:ffff88006bc6fd78 EFLAGS: 00010206
<d>RAX: 001ffffffffd2010 RBX: 001fffff829eee38 RCX: 0000000000000034
<d>RDX: 0000000000001bd7 RSI: 00000000e9009bd6 RDI: ffffffff82a1ce20
<d>RBP: ffff88006bc6fd98 R08: c000000000000000 R09: 4fb0000000000000
<d>R10: 7d80000000000000 R11: 0000000000000000 R12: ffffffff82a1d628
<d>R13: ffffffff82a1ce20 R14: ffff880123768000 R15: ffffffff811d98e0
<d>FS: 0000000000000000(0000) GS:ffff8800cfc40000(0063) knlGS:00000000f74aa6c0
<d>CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b
<d>CR2: 000000000808865c CR3: 000000011b1a4000 CR4: 00000000000006e0
<d>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<d>DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process iknowthis (pid: 12468, threadinfo ffff88006bc6e000, task
ffff88006b525ac0)
<0>Stack:
<c> ffff88006bc6fe78<c> 00000000e9009bd6<c> 0000000000000000<c>
ffffffff82a1ce20<c>
<c> ffff88006bc6fdc8<c> ffffffff810c2aac<c> ffff880018cfc410<c>
ffffffff82a1ce20<c>
<c> 00000000e9009bd6<c> ffffffff811d98e0<c> ffff88006bc6fe28<c>
ffffffff811f3dab<c>
<0>Call Trace:
[1]more>
Only 'q' or 'Q' are processed at more prompt, input ignored
<0> [<ffffffff810c2aac>] find_ge_pid+0x3c/0x50
<0> [<ffffffff811d98e0>] ? compat_fillonedir+0x0/0xe0
<0> [<ffffffff811f3dab>] next_tgid+0x3b/0xc0
<0> [<ffffffff811d98e0>] ? compat_fillonedir+0x0/0xe0
<0> [<ffffffff811f42ec>] proc_pid_readdir+0x13c/0x1d0
<0> [<ffffffff811d98e0>] ? compat_fillonedir+0x0/0xe0
<0> [<ffffffff811f03fa>] proc_root_readdir+0x4a/0x60
<0> [<ffffffff811d98e0>] ? compat_fillonedir+0x0/0xe0
<0> [<ffffffff811a58d0>] vfs_readdir+0xc0/0xe0
<0> [<ffffffff811d8435>] compat_sys_old_readdir+0x45/0x70
<0> [<ffffffff8108b023>] ia32_sysret+0x0/0x5
<0>Code: 89 fd 48 c1 e8 0f 48 c1 e0 04 48 8d 5c 07 08 4c 39 e3 73 54
81 e2 ff 7f 00 00 eb 0f eb 02 90 90 48 83 c3 10 31 d2 49 39 dc 76 3d
<48> 8b 7b 08 48 85 ff 74 ec 48 63 d2 be 00 80 00 00 e8 6f a4 41
Call Trace:
[<ffffffff810c2aac>] find_ge_pid+0x3c/0x50
[<ffffffff811d98e0>] ? compat_fillonedir+0x0/0xe0
[<ffffffff811f3dab>] next_tgid+0x3b/0xc0
[<ffffffff811d98e0>] ? compat_fillonedir+0x0/0xe0
[<ffffffff811f42ec>] proc_pid_readdir+0x13c/0x1d0
[<ffffffff811d98e0>] ? compat_fillonedir+0x0/0xe0
[<ffffffff811f03fa>] proc_root_readdir+0x4a/0x60
[<ffffffff811d98e0>] ? compat_fillonedir+0x0/0xe0
[<ffffffff811a58d0>] vfs_readdir+0xc0/0xe0
[1]more>
Only 'q' or 'Q' are processed at more prompt, input ignored
[<ffffffff811d8435>] compat_sys_old_readdir+0x45/0x70
[<ffffffff8108b023>] ia32_sysret+0x0/0x5



--
Robert ÅwiÄcki
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