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block: blk-mq: fix UAF in blk_mq_tagset_busy_iter #785

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block: blk-mq: fix UAF in blk_mq_tagset_busy_iter #785

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d3df981
Merge branch 'block-7.1' into for-next
axboe Apr 28, 2026
fb9d71c
Merge branch 'io_uring-7.1' into for-next
axboe Apr 28, 2026
bab430f
Dummy commit
kawasaki Apr 30, 2026
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3 changes: 2 additions & 1 deletion include/uapi/linux/io_uring.h
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Original file line number Diff line number Diff line change
Expand Up @@ -905,7 +905,8 @@ struct io_uring_buf_reg {
__u32 ring_entries;
__u16 bgid;
__u16 flags;
__u64 resv[3];
__u32 min_left;
__u32 resv[5];
};

/* argument for IORING_REGISTER_PBUF_STATUS */
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9 changes: 7 additions & 2 deletions io_uring/kbuf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@ static bool io_kbuf_inc_commit(struct io_buffer_list *bl, int len)
this_len = min_t(u32, len, buf_len);
buf_len -= this_len;
/* Stop looping for invalid buffer length of 0 */
if (buf_len || !this_len) {
if (buf_len > bl->min_left_sub_one || !this_len) {
WRITE_ONCE(buf->addr, READ_ONCE(buf->addr) + this_len);
WRITE_ONCE(buf->len, buf_len);
return false;
Expand Down Expand Up @@ -637,6 +637,10 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
if (reg.ring_entries >= 65536)
return -EINVAL;

/* minimum left byte count is a property of incremental buffers */
if (!(reg.flags & IOU_PBUF_RING_INC) && reg.min_left)
return -EINVAL;

bl = io_buffer_get_list(ctx, reg.bgid);
if (bl) {
/* if mapped buffer ring OR classic exists, don't allow */
Expand Down Expand Up @@ -680,10 +684,11 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
}
#endif

bl->nr_entries = reg.ring_entries;
bl->mask = reg.ring_entries - 1;
bl->flags |= IOBL_BUF_RING;
bl->buf_ring = br;
if (reg.min_left)
bl->min_left_sub_one = reg.min_left - 1;
if (reg.flags & IOU_PBUF_RING_INC)
bl->flags |= IOBL_INC;
ret = io_buffer_add_list(ctx, bl, reg.bgid);
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8 changes: 7 additions & 1 deletion io_uring/kbuf.h
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Original file line number Diff line number Diff line change
Expand Up @@ -27,12 +27,18 @@ struct io_buffer_list {
__u16 bgid;

/* below is for ring provided buffers */
__u16 nr_entries;
__u16 head;
__u16 mask;

__u16 flags;

/*
* minimum required amount to be left to reuse an incrementally
* consumed buffer. If less than this is left at consumption time,
* buffer is done and head is incremented to the next buffer.
*/
__u32 min_left_sub_one;

struct io_mapped_region region;
};

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2 changes: 2 additions & 0 deletions io_uring/napi.c
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Expand Up @@ -276,6 +276,8 @@ static int io_napi_register_napi(struct io_ring_ctx *ctx,
/* clean the napi list for new settings */
io_napi_free(ctx);
WRITE_ONCE(ctx->napi_track_mode, napi->op_param);
/* cap NAPI at 10 msec of spin time */
napi->busy_poll_to = min(10000, napi->busy_poll_to);
WRITE_ONCE(ctx->napi_busy_poll_dt, napi->busy_poll_to * NSEC_PER_USEC);
WRITE_ONCE(ctx->napi_prefer_busy_poll, !!napi->prefer_busy_poll);
return 0;
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