2.4.0-test10 oopses (bug in devfs)

Just a note that this oops still occurs in test10. The problem occurs because get_devfs_entry_from_vfs_inode in devfs_follow_link (and/or devfs_read_link), seems to return invalid or incorrect devfs entries whose .u.symlink.linkname is null which causes the line:

        if (*link == '/') {

in fs/namei.c: __vfs_follow_link to oops.

The oops is due to trying to follow an sg? link in /dev.

Nick.

----- Original Message -----
From: "Nick Piggin" <[email protected]>
To: "Linux-Kernel" <[email protected]>
Sent: Wednesday, October 25, 2000 9:16 PM
Subject: 2.4.0-test9 Oopses

Quoted 1 line

Did the following with 2.4.0-test9 + reiserfs 3.6.18 (all ext2

Quoted 14 lines

however) and all ide block devices.

scsi0 : SCSI host adapter emulation for IDE ATAPI devices
Vendor: RICOH     Model: CD-R/RW MP7060A   Rev: 1.50
Type:   CD-ROM                             ANSI SCSI revision: 02
Vendor: ATAPI     Model: CD-ROM DRIVE-24X  Rev: U40M
Type:   CD-ROM                             ANSI SCSI revision: 02

Detected scsi CD-ROM sr0 at scsi0, channel 0, id 0, lun 0 Detected scsi CD-ROM sr1 at scsi0, channel 0, id 1, lun 0
sr0: scsi3-mmc drive: 24x/24x writer cd/rw xa/form2 cdda tray
sr1: scsi3-mmc drive: 20x/20x xa/form2 cdda tray scsi : 0 hosts left.

(loaded ide-scsi modules as you can see)

[snip]

Quoted 4 lines

Doing cdrecord -scanbus I
got these two oopses

Unable to handle kernel NULL pointer dereference at virtual address

00000000

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printing eip:
c013a551

Oops: 0000
CPU:    0
EIP:    0010:[vfs_follow_link+33/368]
EFLAGS: 00010217
eax: 00000000   ebx: c3c5bf90   ecx: 00000341   edx: c02b6040
esi: 00000000   edi: 00000000   ebp: 00000000   esp: c3c5befc
ds: 0018   es: 0018   ss: 0018
Process devfsd (pid: 12, stackpage=c3c5b000)
Stack: c3c5bf90 00000000 c0a01e20 c3c5bf90 00000000 c01547cf c3c5bf90
00000000
       c3c5a000 c0138143 c0a01e20 c3c5bf90 c09c0b40 c3d69000 00000000
c3c5bf90
       bfffecdc 00000001 bfffecdc c3c5bf94 00000009 c0a01e20 c3d69005
00000003
Call Trace: [devfs_follow_link+31/48] [path_walk+1683/1952]
[__user_walk+60/96] [sys_chown+22/80] [sys_chown16+48/64]
[system_call+51/56]
Code: 80 3f 2f 0f 85 c6 00 00 00 53 e8 90 d2 ff ff ba 00 e0 ff ff

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Unable to handle kernel NULL pointer dereference at virtual address

00000000

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printing eip:
c013a551

Oops: 0000
CPU:    0
EIP:    0010:[vfs_follow_link+33/368]
EFLAGS: 00010217
eax: 00000000   ebx: c081df80   ecx: 00000341   edx: c02b6040
esi: c0a01b20   edi: 00000000   ebp: 00000000   esp: c081ded0
ds: 0018   es: 0018   ss: 0018
Process cdrecord (pid: 758, stackpage=c081d000)
Stack: c081df80 c0a01b20 c0a01b20 c081df80 00000000 c01547cf c081df80
00000000
       c081c000 c0138143 c0a01b20 c081df80 c09c0b40 c117d000 00000000
00000002
       00000003 00000001 08074094 c081df84 00000001 c0a01b20 c117d005
00000003
Call Trace: [devfs_follow_link+31/48] [path_walk+1683/1952]
[open_namei+128/1504] [filp_open+59/96] [sys_open+67/208]
[system_call+51/56]
Code: 80 3f 2f 0f 85 c6 00 00 00 53 e8 90 d2 ff ff ba 00 e0 ff ff