On Sun, 5 Mar 2023 21:44:55 +0800
Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx> wrote:
> As the call trace shown, the root cause is kunmap incorrect pages:
>
> BUG: kernel NULL pointer dereference, address: 00000000
> CPU: 1 PID: 40 Comm: kworker/u5:0 Not tainted 6.2.0-rc5 #4
> Workqueue: erofs_worker z_erofs_decompressqueue_work
> EIP: z_erofs_lzma_decompress+0x34b/0x8ac
> z_erofs_decompress+0x12/0x14
> z_erofs_decompress_queue+0x7e7/0xb1c
> z_erofs_decompressqueue_work+0x32/0x60
> process_one_work+0x24b/0x4d8
> ? process_one_work+0x1a4/0x4d8
> worker_thread+0x14c/0x3fc
> kthread+0xe6/0x10c
> ? rescuer_thread+0x358/0x358
> ? kthread_complete_and_exit+0x18/0x18
> ret_from_fork+0x1c/0x28
> ---[ end trace 0000000000000000 ]---
>
> The bug is trivial and should be fixed now. It has no impact on
> !HIGHMEM platforms.
>
> Fixes: 622ceaddb764 ("erofs: lzma compression support")
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.16+
> Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Reviewed-by: Yue Hu <huyue2@xxxxxxxxxxx>
> ---
> fs/erofs/decompressor_lzma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c
> index 091fd5adf818..5cd612a8f858 100644
> --- a/fs/erofs/decompressor_lzma.c
> +++ b/fs/erofs/decompressor_lzma.c
> @@ -278,7 +278,7 @@ int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq,
> }
> }
> if (no < nrpages_out && strm->buf.out)
> - kunmap(rq->in[no]);
> + kunmap(rq->out[no]);
> if (ni < nrpages_in)
> kunmap(rq->in[ni]);
> /* 4. push back LZMA stream context to the global list */
