Bug 247464 - soft lockup in cifs mountpoint leads to unresponsive server
soft lockup in cifs mountpoint leads to unresponsive server
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
low Severity high
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Assigned To: Jeff Layton
Martin Jenner
Depends On:
  Show dependency treegraph
Reported: 2007-07-09 10:23 EDT by Arenas Belon, Carlo Marcelo
Modified: 2008-01-15 06:24 EST (History)
2 users (show)

See Also:
Fixed In Version: RHEL5.1
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2008-01-15 06:24:07 EST
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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External Trackers
Tracker ID Priority Status Summary Last Updated
Linux Kernel 7903 None None None Never

  None (edit)
Description Arenas Belon, Carlo Marcelo 2007-07-09 10:23:05 EDT
Description of problem:
soft lockup in cifs module when doing "stat", as shown by :

kernel: BUG: soft lockup detected on CPU#1!
kernel: [<c0447f3f>] softlockup_tick+0x98/0xa6
kernel: [<c042d138>] update_process_times+0x39/0x5c
kernel: [<c04176f0>] smp_apic_timer_interrupt+0x5c/0x64
kernel: [<c04049bf>] apic_timer_interrupt+0x1f/0x24
kernel: [<c0470f5e>] generic_fillattr+0x76/0xa4
kernel: [<f8d9cce8>] cifs_getattr+0x1e/0x2b [cifs]
kernel: [<f8d9ccca>] cifs_getattr+0x0/0x2b [cifs]
kernel: [<c047132e>] vfs_getattr+0x40/0x9b
kernel: [<c0471445>] vfs_stat_fd+0x2a/0x3c
kernel: [<c04714e4>] sys_stat64+0xf/0x23
kernel: [<c04dec11>] copy_to_user+0x31/0x48
kernel: [<c0403eff>] syscall_call+0x7/0xb
kernel: ======================= 

Version-Release number of selected component (if applicable):

How reproducible:
regularly (4 cases reported in the last 2 days from a universe of 336 boxes)

Steps to Reproduce:
1. create a read only mountpoint to a samba server
2. run 2 processes (better more) in an SMP server with a PAE enabled kernel that
stat files in that mount point
3. wait for it to lock (ping will work, but won't be able to ssh anymore)
Actual results:
system locks and requires a manual reboot (not even sysrq will respond in the

Expected results:
no lock

Additional info:
in the server the smb process is still up and connected from the defunct server,
including oplocks to the file that was being stat as exclusive.

the TCP/IP stack of the defunct server seems to be operative, but no process
that requires a fork/exec would work (rsync/sshd) and will hung TCP connections
after the 3 way handshake is completed.

probably already fixed upstream in version of cifs 1.48 as shown by the linked
bug, with the commit linked in URL
Comment 1 Jeff Layton 2007-07-10 08:01:44 EDT
There's a pending update of the CIFS code already slated for inclusion into 5.1.
If you have a non-critical place to do so, could you test the kernels on my
people page and see if they help this issue:

Comment 2 Jeff Layton 2008-01-15 06:24:07 EST
No response to my query from July. I believe this is already fixed in the 5.1
release. Please reopen if that is not the case.

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