mptcp: fix BUILD_BUG_ON on legacy ARM config

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The 0-day bot managed to find kernel configs that cause build failures,
e.g. when using the StrongARM SA1100 target (ARMv4).

On such legacy ARM architecture, all structures are apparently aligned
to 32 bits, causing build issue here. Indeed, on such architecture,
'flags' size is not equivalent to sizeof(u16) as expected, but to
sizeof(u32).

Instead, use memset(). It was not used before to ensure a simple clear
operation was used by the compiler. But at the end, it shouldn't matter,
and the compiler should optimise this to the same operation with or
without memset() when -O above 0 is used. So let's switch to memset() to
fix this issue, and reduce this complexity.

Fixes: 5e939544f9 ("mptcp: fix uninit-value in mptcp_established_options")
Cc: stable@vger.kernel.org
Suggested-by: Frank Ranner <frank.ranner@intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202605312026.Srgsz7Tp-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202607031100.upQfRZTM-lkp@intel.com/
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260722-net-mptcp-misc-fixes-7-2-rc5-v1-5-6fb595bc86ef@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

This commit is contained in:

Matthieu Baerts (NGI0) 2026-07-22 00:14:42 +02:00 • committed by Jakub Kicinski

parent e3213292c4

commit 133cca19d7

1 changed files with 1 additions and 4 deletions

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net/mptcp/options.c

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