[LU-17418] Lustre crashed immediately after load with debug kernel

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.16.0
• Environment: RHEL 8.5 debug kernel
• Severity: 3
• Assignee: James A Simmons
• Reporter: Alexey Lyashkov

Description

LU-9859 libcfs: refactor libcfs initialization. had removed libcfs debug init from libcfs module init itself.
it caused a panic if debug settings will applied after module load.

crash7> bt
PID: 11558  TASK: ffff888113890000  CPU: 1   COMMAND: "lt-lctl"
 #0 [ffff88810ab5f848] __show_regs at ffffffff8186a0c5
 #1 [ffff88810ab5f8d0] general_protection at ffffffff83a0115e
    [exception RIP: cfs_trace_lock_tcd+37]
    RIP: ffffffffc1495a95  RSP: ffff88810ab5f988  RFLAGS: 00010296
    RAX: dffffc0000000000  RBX: 00000000000000c0  RCX: ffffffffc14d3580
    RDX: 0000000000000029  RSI: 0000000000000000  RDI: 000000000000014c
    RBP: ffff88810ab5fbb0   R8: 0000000000000001   R9: 00000000130e0580
    R10: ffff88810ab5fbc8  R11: ffffed102270b633  R12: 00000000000000c0
    R13: ffffffffc14902a0  R14: 0000000000000001  R15: 0000000000000000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #2 [ffff88810ab5f998] libcfs_debug_msg at ffffffffc1496bec [libcfs]
 #3 [ffff88810ab5fbc0] cfs_str2mask at ffffffffc149e1b5 [libcfs]
 #4 [ffff88810ab5fc30] libcfs_debug_str2mask at ffffffffc149117b [libcfs]
 #5 [ffff88810ab5fd20] proc_dobitmasks at ffffffffc1492c90 [libcfs]
 #6 [ffff88810ab5fd70] lnet_debugfs_write at ffffffffc1491d44 [libcfs]
 #7 [ffff88810ab5fe00] full_proxy_write at ffffffff8242f903
 #8 [ffff88810ab5fe48] vfs_write at ffffffff8220ca57
 #9 [ffff88810ab5fe88] ksys_write at ffffffff8220d218
#10 [ffff88810ab5ff28] do_syscall_64 at ffffffff81809865
#11 [ffff88810ab5ff50] entry_SYSCALL_64_after_hwframe at ffffffff83a000b2
    RIP: 00007fed5c5e5915  RSP: 00007ffdaaa3f9c8  RFLAGS: 00000246
    RAX: ffffffffffffffda  RBX: 00007ffdaaa43422  RCX: 00007fed5c5e5915
    RDX: 000000000000001c  RSI: 00007ffdaaa43422  RDI: 0000000000000003
    RBP: 0000000000000003   R8: 0000000000000800   R9: 0000000000000003
    R10: 000000000000000b  R11: 0000000000000246  R12: 00007ffdaaa41bb8
    R13: 00000000017252a0  R14: 00000000017252e0  R15: 0000000000000000
    ORIG_RAX: 0000000000000001  CS: 0033  SS: 002b

lets restore old behavior.

Issue Links

• is related to: LU-14428 Convert tracefile to use ring_buffer from linux