Messages in this thread Patch in this message | | | Subject | Re: [PATCH 1/2] pipe: fix potential use-after-free in pipe_read() | From | "Leizhen (ThunderTown)" <> | Date | Tue, 23 Nov 2021 09:09:42 +0800 |
| |
On 2021/11/15 21:05, Matthew Wilcox wrote: > On Mon, Nov 15, 2021 at 02:13:44PM +0800, Leizhen (ThunderTown) wrote: >> >> >> On 2021/11/15 12:25, Matthew Wilcox wrote: >>> On Mon, Nov 15, 2021 at 11:57:20AM +0800, Zhen Lei wrote: >>>> if (!buf->len) { >>>> + unsigned int __maybe_unused flags = buf->flags; >>> >>> Why __maybe_unused? >> >> It's used only if "#ifdef CONFIG_WATCH_QUEUE". Otherwise, a warning will be reported. > > Better to turn the #ifdef into if (IS_ENABLED())
Hi, Matthew: Thank you for your advice. IS_ENABLED() is a good idea, but when I tried it, I found that the macro 'PIPE_BUF_FLAG_LOSS' and the structure member 'note_loss' were also separated by "ifdef CONFIG_WATCH_QUEUE", so this method is not suitable here.
#ifdef CONFIG_WATCH_QUEUE #define PIPE_BUF_FLAG_LOSS 0x40 /* Message loss happened after this buffer */ #endif
@@ -62,9 +60,7 @@ struct pipe_inode_info { unsigned int tail; unsigned int max_usage; unsigned int ring_size; #ifdef CONFIG_WATCH_QUEUE bool note_loss; #endif
> . >
| |