RHEL7: CPU soft lockup reports in __ext4_es_shrink during shrink slab due to list_sort

Solution Verified - Updated -


  • CPU soft lockup reports in __ext4_es_shrink during shrink slab and inside list_sort
[14632.767362] list passed to list_sort() too long for efficiency
[14646.303029] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [kswapd0:516]

crash> bt
PID: 505    TASK: ffff88fe7aee4f10  CPU: 36  COMMAND: "kswapd0"
 #0 [ffff887e7ce83cf8] machine_kexec at ffffffff8105d77b
 #1 [ffff887e7ce83d58] __crash_kexec at ffffffff81108732
 #2 [ffff887e7ce83e28] panic at ffffffff816a863f
 #3 [ffff887e7ce83ea8] watchdog_timer_fn at ffffffff811334e1
 #4 [ffff887e7ce83ee0] __hrtimer_run_queues at ffffffff810b8196
 #5 [ffff887e7ce83f38] hrtimer_interrupt at ffffffff810b872f
 #6 [ffff887e7ce83f80] local_apic_timer_interrupt at ffffffff8105467b
 #7 [ffff887e7ce83f98] smp_apic_timer_interrupt at ffffffff816c4e73
 #8 [ffff887e7ce83fb0] apic_timer_interrupt at ffffffff816c1732
--- <IRQ stack> ---
 #9 [ffff887e7a4dba38] apic_timer_interrupt at ffffffff816c1732
    [exception RIP: ext4_inode_touch_time_cmp+13]
    RIP: ffffffffc024d57d  RSP: ffff887e7a4dbae8  RFLAGS: 00000282
    RAX: 0000088000080000  RBX: ffffffffffffff10  RCX: 00000003b0afb9af
    RDX: ffff884f35a89790  RSI: ffff887e48307040  RDI: 0000000000000000
    RBP: ffff887e7a4dbbe0   R8: ffff887e7a4dbba0   R9: 000000000156a2c0
    R10: 0000000000000068  R11: 0000000000000000  R12: ffff8818df3ee020
    R13: ffff884305a19790  R14: 00000003bcc12dec  R15: 00000003bcc0fa2c
    ORIG_RAX: ffffffffffffff10  CS: 0010  SS: 0018
#10 [ffff887e7a4dbaf0] list_sort at ffffffff8133c526
#11 [ffff887e7a4dbbe8] __ext4_es_shrink at ffffffffc024da6e [ext4]
#12 [ffff887e7a4dbc60] ext4_es_shrink at ffffffffc024dbf4 [ext4]
#13 [ffff887e7a4dbca8] shrink_slab at ffffffff811999a5
#14 [ffff887e7a4dbd48] balance_pgdat at ffffffff8119d661
#15 [ffff887e7a4dbe20] kswapd at ffffffff8119d903
#16 [ffff887e7a4dbec8] kthread at ffffffff810b4031
#17 [ffff887e7a4dbf50] ret_from_fork at ffffffff816c055d


  • Red Hat Enterprise Linux 7
  • Seen on Kernel-3.10.0-693.21.1.el7 / kernel-3.10.0-1127.el7
  • ext4 filesystem

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