From: Brian Norris <briannorris@chromium.org>
To: Nicolas Boichat <drinkcat@chromium.org>
Cc: Pi-Hsun Shih <pihsun@chromium.org>,
open list <linux-kernel@vger.kernel.org>,
linux-wireless@vger.kernel.org
Subject: Re: [PATCH] wireless: Use offsetof instead of custom macro.
Date: Wed, 27 Nov 2019 15:39:58 -0800 [thread overview]
Message-ID: <20191127233957.GA217817@google.com> (raw)
In-Reply-To: <CANMq1KCwcVawg6L1hTKXBgBi66EKdHQrvxr_chR9Kv1ifFREnA@mail.gmail.com>
+ linux-wireless
[Top-posting because the important stuff is up here, and the rest is
missing from linux-wireless]
Hey Pi-Hsun, Nicolas: you failed to copy linux-wireless, so no one's
going to pick this patch up. Please re-send if you care.
Regards,
Brian
On Thu, May 02, 2019 at 03:56:33PM +0800, Nicolas Boichat wrote:
> On Thu, Apr 18, 2019 at 3:50 PM Pi-Hsun Shih <pihsun@chromium.org> wrote:
> >
> > Use offsetof to calculate offset of a field to take advantage of
> > compiler built-in version when possible, and avoid UBSAN warning when
> > compiling with Clang:
> >
> > ==================================================================
> > UBSAN: Undefined behaviour in net/wireless/wext-core.c:525:14
> > member access within null pointer of type 'struct iw_point'
> > CPU: 3 PID: 165 Comm: kworker/u16:3 Tainted: G S W 4.19.23 #43
> > Workqueue: cfg80211 __cfg80211_scan_done [cfg80211]
> > Call trace:
> > dump_backtrace+0x0/0x194
> > show_stack+0x20/0x2c
> > __dump_stack+0x20/0x28
> > dump_stack+0x70/0x94
> > ubsan_epilogue+0x14/0x44
> > ubsan_type_mismatch_common+0xf4/0xfc
> > __ubsan_handle_type_mismatch_v1+0x34/0x54
> > wireless_send_event+0x3cc/0x470
> > ___cfg80211_scan_done+0x13c/0x220 [cfg80211]
> > __cfg80211_scan_done+0x28/0x34 [cfg80211]
> > process_one_work+0x170/0x35c
> > worker_thread+0x254/0x380
> > kthread+0x13c/0x158
> > ret_from_fork+0x10/0x18
> > ===================================================================
> >
> > Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
>
> The warning from clang is spurious, but in another case, we felt that
> the cleanup was worth it, nevertheless
> (https://lore.kernel.org/patchwork/patch/1050040/).
>
> Reviewed-By: Nicolas Boichat <drinkcat@chromium.org>
>
> > ---
> > include/uapi/linux/wireless.h | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/include/uapi/linux/wireless.h b/include/uapi/linux/wireless.h
> > index 86eca3208b6b..f259cca5cc2b 100644
> > --- a/include/uapi/linux/wireless.h
> > +++ b/include/uapi/linux/wireless.h
> > @@ -1090,8 +1090,7 @@ struct iw_event {
> > /* iw_point events are special. First, the payload (extra data) come at
> > * the end of the event, so they are bigger than IW_EV_POINT_LEN. Second,
> > * we omit the pointer, so start at an offset. */
> > -#define IW_EV_POINT_OFF (((char *) &(((struct iw_point *) NULL)->length)) - \
> > - (char *) NULL)
> > +#define IW_EV_POINT_OFF offsetof(struct iw_point, length)
> > #define IW_EV_POINT_LEN (IW_EV_LCP_LEN + sizeof(struct iw_point) - \
> > IW_EV_POINT_OFF)
> >
> > --
> > 2.21.0.392.gf8f6787159e-goog
> >
parent reply other threads:[~2019-11-27 23:40 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <CANMq1KCwcVawg6L1hTKXBgBi66EKdHQrvxr_chR9Kv1ifFREnA@mail.gmail.com>]
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