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block: fix error in handling dead task for ioprio setting

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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 <dan.carpenter@oracle.com>
Reported-by: syzbot+8836466a79f4175961b0@syzkaller.appspotmail.com
Fixes: 5fc11eebb4 ("block: open code create_task_io_context in set_task_ioprio")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2021-12-20 20:32:24 -07:00
parent 518579a9af
commit a957b61254
1 changed files with 8 additions and 2 deletions
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10
block/blk-ioc.c
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@ -279,7 +279,12 @@ int set_task_ioprio(struct task_struct *task, int ioprio)
return -ENOMEM; return -ENOMEM;
task_lock(task); 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); kmem_cache_free(iocontext_cachep, ioc);
ioc = task->io_context; ioc = task->io_context;
} else { } else {
@ -287,8 +292,9 @@ int set_task_ioprio(struct task_struct *task, int ioprio)
} }
} }
task->io_context->ioprio = ioprio; task->io_context->ioprio = ioprio;
out:
task_unlock(task); task_unlock(task);
return 0; return err;
} }
EXPORT_SYMBOL_GPL(set_task_ioprio); EXPORT_SYMBOL_GPL(set_task_ioprio);