On 3/22/26 6:18 AM, Deepanshu Kartikey wrote:
Closes: https://syzkaller.appspot.com/bug?extid=ed8bc247f231c1a48e21
[ ... ]
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 8cd2520b4c99..6cc7d83ed1c2 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -773,7 +773,7 @@ int blk_trace_setup(struct request_queue *q, char *name,
dev_t dev,
if (ret)
return -EFAULT;
- if (!buts.buf_size || !buts.buf_nr)
+ if (buts.buf_size < sizeof(struct blk_io_trace) || !buts.buf_nr)
return -EINVAL;
buts2 = (struct blk_user_trace_setup2) {
Why sizeof(struct blk_io_trace) instead of sizeof(struct blk_io_trace2)?
Even sizeof(struct blk_io_trace2) is too small if any additional data is
included.
Additionally, how can this patch fix the issue mentioned in the linked
syzbot report? Is the syzbot link correct? From the syzbot report:
Oops: general protection fault, probably for non-canonical address
0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:bvec_set_page include/linux/bvec.h:44 [inline]
RIP: 0010:__bio_add_page block/bio.c:992 [inline]
RIP: 0010:bio_add_page+0x462/0x6e0 block/bio.c:1048
Call Trace:
<TASK>
bio_add_folio+0x64/0x90 block/bio.c:1084
io_submit_add_bh fs/ext4/page-io.c:465 [inline]
ext4_bio_write_folio+0x1446/0x1ea0 fs/ext4/page-io.c:603
mpage_map_and_submit_buffers fs/ext4/inode.c:2326 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2516 [inline]
ext4_do_writepages+0x207e/0x46e0 fs/ext4/inode.c:2928
ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3022
do_writepages+0x32e/0x550 mm/page-writeback.c:2554
__writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1750
writeback_sb_inodes+0x992/0x1a20 fs/fs-writeback.c:2042
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2229
wb_check_start_all fs/fs-writeback.c:2355 [inline]
wb_do_writeback fs/fs-writeback.c:2381 [inline]
wb_workfn+0x95b/0xf50 fs/fs-writeback.c:2414
process_one_work+0x9ab/0x1780 kernel/workqueue.c:3288
process_scheduled_works kernel/workqueue.c:3379 [inline]
worker_thread+0xba8/0x11e0 kernel/workqueue.c:3465
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Thanks,
Bart.
