RHEL6.5: writing to named pipe blocks if the associated filesystem is frozen
Issue
- Process blocked in __sb_start_write called from pipe_write
- One or more processes writing to pipes are blocking in
__sb_start_write
with a backtrace similar to the following
[<ffffffff8118b0bc>] __sb_start_write+0xdc/0x120
[<ffffffff81193bff>] pipe_write+0x7f/0x6a0
[<ffffffff81188e0a>] do_sync_write+0xfa/0x140
[<ffffffff81189108>] vfs_write+0xb8/0x1a0
[<ffffffff81189a01>] sys_write+0x51/0x90
[<ffffffff8100b072>] system_call_fastpath+0x16/0x1b
Environment
- Red Hat Enterprise Linux 6.5
- kernels prior to 2.6.32-431.28.1.el6
- application using named pipes (an unnamed pipe will have a pipefs superblock, and won't be freezable)
- application freezing / unfreezing filesystems
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