Hello Jens Axboe,
This is a semi-automatic email about new static checker warnings.
The patch 5cf4f52e6d8a: "io_uring: free io_buffer_list entries via
RCU" from Nov 27, 2023, leads to the following Smatch complaint:
io_uring/kbuf.c:766 io_pbuf_get_address()
warn: variable dereferenced before check 'bl' (see line 764)
io_uring/kbuf.c
753 void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid)
754 {
755 struct io_buffer_list *bl;
756
757 bl = __io_buffer_get_list(ctx, smp_load_acquire(&ctx->io_bl), bgid);
758
759 /*
760 * Ensure the list is fully setup. Only strictly needed for RCU lookup
761 * via mmap, and in that case only for the array indexed groups. For
762 * the xarray lookups, it's either visible and ready, or not at all.
763 */
764 if (!smp_load_acquire(&bl->is_ready))
^^^^^
bl dereferenced here
765 return NULL;
766 if (!bl || !bl->is_mmap)
^^^
Checked for NULL too late.
767 return NULL;
768
769 return bl->buf_ring;
770 }
regards,
dan carpenter
