Revision 0dd1e3773ae8afc4bfdce782bdeffc10f9cae6ec authored by Jan Stancek on 22 December 2019, 12:33:24 UTC, committed by Linus Torvalds on 22 December 2019, 17:47:47 UTC
LTP pipeio_1 test is hanging with v5.5-rc2-385-gb8e382a185eb,
with read side observing empty pipe and sleeping and write
side running out of space and then sleeping as well. In this
scenario there are 5 writers and 1 reader.
Problem is that after pipe_write() reacquires pipe lock, it
re-checks for empty pipe with potentially stale 'head' and
doesn't wake up read side anymore. pipe->tail can advance
beyond 'head', because there are multiple writers.
Use pipe->head for empty pipe check after reacquiring lock
to observe current state.
Testing: With patch, LTP pipeio_1 ran successfully in loop for 1 hour.
Without patch it hanged within a minute.
Fixes: 1b6b26ae7053 ("pipe: fix and clarify pipe write wakeup logic")
Reported-by: Rachel Sibley <rasibley@redhat.com>
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent b8e382a
| File | Mode | Size |
|---|---|---|
| Kconfig | -rw-r--r-- | 1.2 KB |
| Makefile | -rw-r--r-- | 378 bytes |
| acl.c | -rw-r--r-- | 5.8 KB |
| acl.h | -rw-r--r-- | 1.5 KB |
| balloc.c | -rw-r--r-- | 44.7 KB |
| dir.c | -rw-r--r-- | 16.9 KB |
| ext2.h | -rw-r--r-- | 28.1 KB |
| file.c | -rw-r--r-- | 5.2 KB |
| ialloc.c | -rw-r--r-- | 18.3 KB |
| inode.c | -rw-r--r-- | 48.0 KB |
| ioctl.c | -rw-r--r-- | 4.1 KB |
| namei.c | -rw-r--r-- | 9.4 KB |
| super.c | -rw-r--r-- | 44.4 KB |
| symlink.c | -rw-r--r-- | 916 bytes |
| xattr.c | -rw-r--r-- | 28.9 KB |
| xattr.h | -rw-r--r-- | 3.3 KB |
| xattr_security.c | -rw-r--r-- | 1.4 KB |
| xattr_trusted.c | -rw-r--r-- | 1.1 KB |
| xattr_user.c | -rw-r--r-- | 1.2 KB |
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