Messages in this thread | | | Date | Sat, 29 Jul 2017 23:27:43 -0700 (PDT) | Subject | Re: [PATCH net] tcp: avoid bogus gcc-7 array-bounds warning | From | David Miller <> |
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From: Arnd Bergmann <arnd@arndb.de> Date: Fri, 28 Jul 2017 16:41:37 +0200
> When using CONFIG_UBSAN_SANITIZE_ALL, the TCP code produces a > false-positive warning: > > net/ipv4/tcp_output.c: In function 'tcp_connect': > net/ipv4/tcp_output.c:2207:40: error: array subscript is below array bounds [-Werror=array-bounds] > tp->chrono_stat[tp->chrono_type - 1] += now - tp->chrono_start; > ^~ > net/ipv4/tcp_output.c:2207:40: error: array subscript is below array bounds [-Werror=array-bounds] > tp->chrono_stat[tp->chrono_type - 1] += now - tp->chrono_start; > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~ > > I have opened a gcc bug for this, but distros have already shipped > compilers with this problem, and it's not clear yet whether there is > a way for gcc to avoid the warning. As the problem is related to the > bitfield access, this introduces a temporary variable to store the old > enum value. > > I did not notice this warning earlier, since UBSAN is disabled when > building with COMPILE_TEST, and that was always turned on in both > allmodconfig and randconfig tests. > > Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81601 > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Applied, thanks Arnd.
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