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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