Messages in this thread Patch in this message | | | Date | Wed, 24 Mar 2021 15:23:32 +0100 | From | Lukas Schauer <> | Subject | [PATCH] fs/pipe: wakeup wr_wait after setting max_usage |
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With commit c73be61cede5882f9605a852414db559c0ebedfd a regression was introduced that would lock up resized pipes under certain conditions.
In that commit resizing the pipe ring size was moved to a different function, doing that moved the wakeup for pipe->wr_wait before actually raising pipe->max_usage. If a pipe was full before the resize occured it would result in the wakeup never actually triggering pipe_write, resulting in a deadlock.
This patch moves the wakeup for pipe->wr_wait back to the original pipe_set_size function, after pipe->max_usage has actually been updated. --- fs/pipe.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/pipe.c b/fs/pipe.c index bfd946a9ad01..58916ad905b4 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -1282,8 +1282,6 @@ int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots) pipe->tail = tail; pipe->head = head;
- /* This might have made more room for writers */ - wake_up_interruptible(&pipe->wr_wait); return 0; }
@@ -1335,6 +1333,10 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
pipe->max_usage = nr_slots; pipe->nr_accounted = nr_slots; + + /* This might have made more room for writers */ + wake_up_interruptible(&pipe->wr_wait); + return pipe->max_usage * PAGE_SIZE;
out_revert_acct: -- 2.31.0
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