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): 2.6.18-8.1.6.el5PAE 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 console) 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
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: http://people.redhat.com/jlayton
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.