[LU-12094] NULL pointer dereference in lprocfs_import_seq_write

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.13.0
• Severity: 3
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

BUG: unable to handle kernel NULL pointer dereference at 00000000000003c4
RIP: 0010:[<ffffffffa007b2cf>] [<ffffffffa007b2cf>] lprocfs_import_seq_write+0x11f/0x520 [ptlrpc]
Call Trace:
[<ffffffffa03830e7>] mdc_import_seq_write+0x17/0x20 [mdc]
[<ffffffff81229bcd>] proc_reg_write+0x3d/0x70
[<ffffffff811b5a78>] vfs_write+0xb8/0x1d0
[<ffffffff811b6899>] SyS_write+0x69/0x110
[<ffffffff815fc6d8>] tracesys+0x8a/0xb0

looks like a race as imp was NULL:
(gdb) p &((struct obd_import *)0)->imp_connect_data.ocd_instance
$2 = (__u32 *) 0x3c4 <_ldlm_lock_debug+228>