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https://kernel.googlesource.com/pub/scm/linux/kernel/git/stable/linux-stable.git
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838b35bb6a
If an application does O_DIRECT writes with io_uring and the file system
supports IOCB_DIO_CALLER_COMP, then completions of the dio write side is
done from the task_work that will post the completion event for said
write as well.
Whenever a dio write is done against a file, the inode i_dio_count is
elevated. This enables other callers to use inode_dio_wait() to wait for
previous writes to complete. If we defer the full dio completion to
task_work, we are dependent on that task_work being run before the
inode i_dio_count can be decremented.
If the same task that issues io_uring dio writes with
IOCB_DIO_CALLER_COMP performs a synchronous system call that calls
inode_dio_wait(), then we can deadlock as we're blocked sleeping on
the event to become true, but not processing the completions that will
result in the inode i_dio_count being decremented.
Until we can guarantee that this is the case, then disable the deferred
caller completions.
Fixes:
|
||
|---|---|---|
| .. | ||
| advise.c | ||
| advise.h | ||
| alloc_cache.h | ||
| cancel.c | ||
| cancel.h | ||
| epoll.c | ||
| epoll.h | ||
| fdinfo.c | ||
| fdinfo.h | ||
| filetable.c | ||
| filetable.h | ||
| fs.c | ||
| fs.h | ||
| io_uring.c | ||
| io_uring.h | ||
| io-wq.c | ||
| io-wq.h | ||
| kbuf.c | ||
| kbuf.h | ||
| Makefile | ||
| msg_ring.c | ||
| msg_ring.h | ||
| net.c | ||
| net.h | ||
| nop.c | ||
| nop.h | ||
| notif.c | ||
| notif.h | ||
| opdef.c | ||
| opdef.h | ||
| openclose.c | ||
| openclose.h | ||
| poll.c | ||
| poll.h | ||
| refs.h | ||
| rsrc.c | ||
| rsrc.h | ||
| rw.c | ||
| rw.h | ||
| slist.h | ||
| splice.c | ||
| splice.h | ||
| sqpoll.c | ||
| sqpoll.h | ||
| statx.c | ||
| statx.h | ||
| sync.c | ||
| sync.h | ||
| tctx.c | ||
| tctx.h | ||
| timeout.c | ||
| timeout.h | ||
| uring_cmd.c | ||
| uring_cmd.h | ||
| xattr.c | ||
| xattr.h | ||