5.4-stable review patch. If anyone has any objections, please let me know.
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From: Bart Van Assche bvanassche@acm.org
commit b820de741ae48ccf50dd95e297889c286ff4f760 upstream.
If kiocb_set_cancel_fn() is called for I/O submitted via io_uring, the following kernel warning appears:
WARNING: CPU: 3 PID: 368 at fs/aio.c:598 kiocb_set_cancel_fn+0x9c/0xa8 Call trace: kiocb_set_cancel_fn+0x9c/0xa8 ffs_epfile_read_iter+0x144/0x1d0 io_read+0x19c/0x498 io_issue_sqe+0x118/0x27c io_submit_sqes+0x25c/0x5fc __arm64_sys_io_uring_enter+0x104/0xab0 invoke_syscall+0x58/0x11c el0_svc_common+0xb4/0xf4 do_el0_svc+0x2c/0xb0 el0_svc+0x2c/0xa4 el0t_64_sync_handler+0x68/0xb4 el0t_64_sync+0x1a4/0x1a8
Fix this by setting the IOCB_AIO_RW flag for read and write I/O that is submitted by libaio.
Suggested-by: Jens Axboe axboe@kernel.dk Cc: Christoph Hellwig hch@lst.de Cc: Avi Kivity avi@scylladb.com Cc: Sandeep Dhavale dhavale@google.com Cc: Jens Axboe axboe@kernel.dk Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Kent Overstreet kent.overstreet@linux.dev Cc: stable@vger.kernel.org Signed-off-by: Bart Van Assche bvanassche@acm.org Link: https://lore.kernel.org/r/20240215204739.2677806-2-bvanassche@acm.org Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/aio.c | 9 ++++++++- include/linux/fs.h | 2 ++ 2 files changed, 10 insertions(+), 1 deletion(-)
--- a/fs/aio.c +++ b/fs/aio.c @@ -570,6 +570,13 @@ void kiocb_set_cancel_fn(struct kiocb *i struct kioctx *ctx = req->ki_ctx; unsigned long flags;
+ /* + * kiocb didn't come from aio or is neither a read nor a write, hence + * ignore it. + */ + if (!(iocb->ki_flags & IOCB_AIO_RW)) + return; + if (WARN_ON_ONCE(!list_empty(&req->ki_list))) return;
@@ -1455,7 +1462,7 @@ static int aio_prep_rw(struct kiocb *req req->ki_complete = aio_complete_rw; req->private = NULL; req->ki_pos = iocb->aio_offset; - req->ki_flags = iocb_flags(req->ki_filp); + req->ki_flags = iocb_flags(req->ki_filp) | IOCB_AIO_RW; if (iocb->aio_flags & IOCB_FLAG_RESFD) req->ki_flags |= IOCB_EVENTFD; req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp)); --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -314,6 +314,8 @@ enum rw_hint { #define IOCB_SYNC (1 << 5) #define IOCB_WRITE (1 << 6) #define IOCB_NOWAIT (1 << 7) +/* kiocb is a read or write operation submitted by fs/aio.c. */ +#define IOCB_AIO_RW (1 << 23)
struct kiocb { struct file *ki_filp;