On 1/16/17 10:39 PM, jeffm@xxxxxxxx wrote:
> From: Jeff Mahoney <jeffm@xxxxxxxx>
>
> pf_queuing_worker and pf_create_prefetch_thread both try to handle
> thread creation failure gracefully, but assume that pthread_create
> doesn't modify the pthread_t when it fails.
>
> From the pthread_create man page:
> On success, pthread_create() returns 0; on error, it returns an error
> number, and the contents of *thread are undefined.
>
> In fact, glibc's pthread_create writes the pthread_t value before
> calling clone(). When we join the created threads in
> cleanup_inode_prefetch and the cleanup stage of pf_queuing_worker, we
> assume that if the pthread_t is nonzero that it's a valid thread handle
> and end up crashing in pthread_join.
>
> This patch zeros out the handle after pthread_create failure.
>
> Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
Sweeping up old patches, sorry for missing these.
Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
> repair/prefetch.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/repair/prefetch.c b/repair/prefetch.c
> index ff50606..044fab2 100644
> --- a/repair/prefetch.c
> +++ b/repair/prefetch.c
> @@ -703,6 +703,7 @@ pf_queuing_worker(
> if (err != 0) {
> do_warn(_("failed to create prefetch thread: %s\n"),
> strerror(err));
> + args->io_threads[i] = 0;
> if (i == 0) {
> pf_start_processing(args);
> return NULL;
> @@ -816,6 +817,7 @@ pf_create_prefetch_thread(
> if (err != 0) {
> do_warn(_("failed to create prefetch thread: %s\n"),
> strerror(err));
> + args->queuing_thread = 0;
> cleanup_inode_prefetch(args);
> }
>
>
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