| Message ID | 20230516074554.1674536-1-arnd@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | wifi: b43: fix incorrect __packed annotation | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Tue, May 16, 2023 at 09:45:42AM +0200, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > clang warns about an unpacked structure inside of a packed one: > > drivers/net/wireless/broadcom/b43/b43.h:654:4: error: field data within 'struct b43_iv' is less aligned than 'union (unnamed union at /home/arnd/arm-soc/drivers/net/wireless/broadcom/b43/b43.h:651:2)' and is usually due to 'struct b43_iv' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access] > > The problem here is that the anonymous union has the default alignment > from its members, apparently because the original author mixed up the > placement of the __packed attribute by placing it next to the struct > member rather than the union definition. As the struct itself is > also marked as __packed, there is no need to mark its members, so just > move the annotation to the inner type instead. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Simon Horman <simon.horman@corigine.com>
On Tue, 16 May 2023 09:45:42 +0200 Arnd Bergmann <arnd@kernel.org> wrote: > b43_iv { union { > __be16 d16; > __be32 d32; > - } data __packed; > + } __packed data; > } __packed; > > Oh, interesting. This has probably been there forever. Did you check if the b43legacy driver has the same issue? Acked-by: Michael Büsch <m@bues.ch>
On Tue, May 16, 2023, at 19:12, Michael Büsch wrote: > On Tue, 16 May 2023 09:45:42 +0200 > Arnd Bergmann <arnd@kernel.org> wrote: > >> b43_iv { union { >> __be16 d16; >> __be32 d32; >> - } data __packed; >> + } __packed data; >> } __packed; >> >> > > Oh, interesting. This has probably been there forever. > Did you check if the b43legacy driver has the same issue? I had not checked, but I see that it does have the same bug. I only sent this one because the build bot (incorrectly) blamed one of my recent patches for a regression here. Which reminds me that I was missing: Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/oe-kbuild-all/202305160749.ay1HAoyP-lkp@intel.com/ Should I resend this as a combined patch for both drivers? Arnd
On Tue, 16 May 2023 19:45:16 +0200
"Arnd Bergmann" <arnd@arndb.de> wrote:
> Should I resend this as a combined patch for both drivers?
I think that would be fine, yes.
Thank you for checking.
On 5/16/23 02:45, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > clang warns about an unpacked structure inside of a packed one: > > drivers/net/wireless/broadcom/b43/b43.h:654:4: error: field data within 'struct b43_iv' is less aligned than 'union (unnamed union at /home/arnd/arm-soc/drivers/net/wireless/broadcom/b43/b43.h:651:2)' and is usually due to 'struct b43_iv' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access] > > The problem here is that the anonymous union has the default alignment > from its members, apparently because the original author mixed up the > placement of the __packed attribute by placing it next to the struct > member rather than the union definition. As the struct itself is > also marked as __packed, there is no need to mark its members, so just > move the annotation to the inner type instead. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/net/wireless/broadcom/b43/b43.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/broadcom/b43/b43.h b/drivers/net/wireless/broadcom/b43/b43.h > index 9fc7c088a539..67b4bac048e5 100644 > --- a/drivers/net/wireless/broadcom/b43/b43.h > +++ b/drivers/net/wireless/broadcom/b43/b43.h > @@ -651,7 +651,7 @@ struct b43_iv { > union { > __be16 d16; > __be32 d32; > - } data __packed; > + } __packed data > } __packed; This change works on a BCM4306 and BCM4318=. Tested-by: Larry Finger <Larry.Finger@lwfinger.net> To answer Michael's question, b43legacy has the same issue. Larry Larry
diff --git a/drivers/net/wireless/broadcom/b43/b43.h b/drivers/net/wireless/broadcom/b43/b43.h index 9fc7c088a539..67b4bac048e5 100644 --- a/drivers/net/wireless/broadcom/b43/b43.h +++ b/drivers/net/wireless/broadcom/b43/b43.h @@ -651,7 +651,7 @@ struct b43_iv { union { __be16 d16; __be32 d32; - } data __packed; + } __packed data; } __packed;