From: Jens Axboe Date: Tue, 21 Dec 2021 03:32:24 +0000 (-0700) Subject: block: fix error in handling dead task for ioprio setting X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a957b61254a7;p=linux.git block: fix error in handling dead task for ioprio setting Don't combine the task exiting and "already have io_context" case, we need to just abort if the task is marked as dead. Return -ESRCH, which is the documented value for ioprio_set() if the specified task could not be found. Reported-by: Dan Carpenter Reported-by: syzbot+8836466a79f4175961b0@syzkaller.appspotmail.com Fixes: 5fc11eebb4a9 ("block: open code create_task_io_context in set_task_ioprio") Signed-off-by: Jens Axboe --- diff --git a/block/blk-ioc.c b/block/blk-ioc.c index 87bdc9ca82959..71c3a933cf161 100644 --- a/block/blk-ioc.c +++ b/block/blk-ioc.c @@ -279,7 +279,12 @@ int set_task_ioprio(struct task_struct *task, int ioprio) return -ENOMEM; task_lock(task); - if (task->io_context || (task->flags & PF_EXITING)) { + if (task->flags & PF_EXITING) { + err = -ESRCH; + kmem_cache_free(iocontext_cachep, ioc); + goto out; + } + if (task->io_context) { kmem_cache_free(iocontext_cachep, ioc); ioc = task->io_context; } else { @@ -287,8 +292,9 @@ int set_task_ioprio(struct task_struct *task, int ioprio) } } task->io_context->ioprio = ioprio; +out: task_unlock(task); - return 0; + return err; } EXPORT_SYMBOL_GPL(set_task_ioprio);