4.9-stable review patch. If anyone has any objections, please let me know.
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From: Martin Brandenburg martin@omnibond.com
commit a0ec1ded22e6a6bc41981fae22406835b006a66e upstream.
In orangefs_devreq_read, there is a loop which picks an op off the list of pending ops. If the loop fails to find an op, there is nothing to read, and it returns EAGAIN. If the op has been given up on, the loop is restarted via a goto. The bug is that the variable which the found op is written to is not reinitialized, so if there are no more eligible ops on the list, the code runs again on the already handled op.
This is triggered by interrupting a process while the op is being copied to the client-core. It's a fairly small window, but it's there.
Signed-off-by: Martin Brandenburg martin@omnibond.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/orangefs/devorangefs-req.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/orangefs/devorangefs-req.c +++ b/fs/orangefs/devorangefs-req.c @@ -161,7 +161,7 @@ static ssize_t orangefs_devreq_read(stru struct orangefs_kernel_op_s *op, *temp; __s32 proto_ver = ORANGEFS_KERNEL_PROTO_VERSION; static __s32 magic = ORANGEFS_DEVREQ_MAGIC; - struct orangefs_kernel_op_s *cur_op = NULL; + struct orangefs_kernel_op_s *cur_op; unsigned long ret;
/* We do not support blocking IO. */ @@ -181,6 +181,7 @@ static ssize_t orangefs_devreq_read(stru }
restart: + cur_op = NULL; /* Get next op (if any) from top of list. */ spin_lock(&orangefs_request_list_lock); list_for_each_entry_safe(op, temp, &orangefs_request_list, list) {