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-Wc23-extensions in net/ipv4/tcp_output.c #1953

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nathanchance opened this issue Oct 31, 2023 · 4 comments
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-Wc23-extensions in net/ipv4/tcp_output.c #1953

nathanchance opened this issue Oct 31, 2023 · 4 comments
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@nathanchance
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-Wc23-extensions [BUG] linux A bug that should be fixed in the mainline kernel. [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle

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@nathanchance
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net/ipv4/tcp_output.c:663:2: error: label at end of compound statement is a C23 extension [-Werror,-Wc23-extensions]
  663 |         }
      |         ^
1 error generated.

This was a hard error in earlier releases:

net/ipv4/tcp_output.c:663:2: error: expected statement
        }
        ^
1 error generated.

I'll have a patch shortly.
@nathanchance nathanchance added [BUG] linux-next This is an issue only seen in linux-next -Wc23-extensions labels Oct 31, 2023
@nathanchance nathanchance self-assigned this Oct 31, 2023
@nathanchance
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https://lore.kernel.org/20231031-tcp-ao-fix-label-in-compound-statement-warning-v1-1-c9731d115f17@kernel.org/

@nathanchance nathanchance added the [PATCH] Submitted A patch has been submitted for review label Oct 31, 2023
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Oct 31, 2023
@nathanchance @intel-lab-lkp
tcp: Fix -Wc23-extensions in tcp_options_write()
8e6ff55 
Clang warns (or errors with CONFIG_WERROR=y) when CONFIG_TCP_AO is set:

  net/ipv4/tcp_output.c:663:2: error: label at end of compound statement is a C23 extension [-Werror,-Wc23-extensions]
    663 |         }
        |         ^
  1 error generated.

On earlier releases (such as clang-11, the current minimum supported
version for building the kernel) that do not support C23, this was a
hard error unconditionally:

  net/ipv4/tcp_output.c:663:2: error: expected statement
          }
          ^
  1 error generated.

Add a semicolon after the label to create an empty statement, which
resolves the warning or error for all compilers.

Closes: ClangBuiltLinux#1953
Fixes: 1e03d32 ("net/tcp: Add TCP-AO sign to outgoing packets")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
@nickdesaulniers nickdesaulniers added [BUG] linux A bug that should be fixed in the mainline kernel. and removed [BUG] linux-next This is an issue only seen in linux-next labels Nov 1, 2023
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Nov 6, 2023
@nathanchance @intel-lab-lkp
tcp: Fix -Wc23-extensions in tcp_options_write()
32586b2 
Clang warns (or errors with CONFIG_WERROR=y) when CONFIG_TCP_AO is set:

  net/ipv4/tcp_output.c:663:2: error: label at end of compound statement is a C23 extension [-Werror,-Wc23-extensions]
    663 |         }
        |         ^
  1 error generated.

On earlier releases (such as clang-11, the current minimum supported
version for building the kernel) that do not support C23, this was a
hard error unconditionally:

  net/ipv4/tcp_output.c:663:2: error: expected statement
          }
          ^
  1 error generated.

While adding a semicolon after the label would resolve this, it is more
in line with the kernel as a whole to refactor this block into a
standalone function, which means the goto a label construct can just be
replaced with a simple return. Do so to resolve the warning.

Closes: ClangBuiltLinux#1953
Fixes: 1e03d32 ("net/tcp: Add TCP-AO sign to outgoing packets")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
@nathanchance
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v3: https://lore.kernel.org/20231106-tcp-ao-fix-label-in-compound-statement-warning-v3-1-b54a64602a85@kernel.org/

intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Nov 6, 2023
@nathanchance @intel-lab-lkp
tcp: Fix -Wc23-extensions in tcp_options_write()
0764288 
Clang warns (or errors with CONFIG_WERROR=y) when CONFIG_TCP_AO is set:

  net/ipv4/tcp_output.c:663:2: error: label at end of compound statement is a C23 extension [-Werror,-Wc23-extensions]
    663 |         }
        |         ^
  1 error generated.

On earlier releases (such as clang-11, the current minimum supported
version for building the kernel) that do not support C23, this was a
hard error unconditionally:

  net/ipv4/tcp_output.c:663:2: error: expected statement
          }
          ^
  1 error generated.

While adding a semicolon after the label would resolve this, it is more
in line with the kernel as a whole to refactor this block into a
standalone function, which means the goto a label construct can just be
replaced with a return statement. Do so to resolve the warning.

Closes: ClangBuiltLinux#1953
Fixes: 1e03d32 ("net/tcp: Add TCP-AO sign to outgoing packets")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
@nathanchance
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Patch accepted: https://git.kernel.org/netdev/net/c/7425627b2b2cd671d5bf6541ce50f7cba8a76ad6

intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Nov 8, 2023
@nathanchance @davem330
tcp: Fix -Wc23-extensions in tcp_options_write()
7425627 
Clang warns (or errors with CONFIG_WERROR=y) when CONFIG_TCP_AO is set:

  net/ipv4/tcp_output.c:663:2: error: label at end of compound statement is a C23 extension [-Werror,-Wc23-extensions]
    663 |         }
        |         ^
  1 error generated.

On earlier releases (such as clang-11, the current minimum supported
version for building the kernel) that do not support C23, this was a
hard error unconditionally:

  net/ipv4/tcp_output.c:663:2: error: expected statement
          }
          ^
  1 error generated.

While adding a semicolon after the label would resolve this, it is more
in line with the kernel as a whole to refactor this block into a
standalone function, which means the goto a label construct can just be
replaced with a return statement. Do so to resolve the warning.

Closes: ClangBuiltLinux#1953
Fixes: 1e03d32 ("net/tcp: Add TCP-AO sign to outgoing packets")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Dmitry Safonov <dima@arista.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
@nathanchance nathanchance added [PATCH] Accepted A submitted patch has been accepted upstream and removed [PATCH] Submitted A patch has been submitted for review labels Nov 8, 2023
@nathanchance
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Merged into mainline: https://git.kernel.org/linus/7425627b2b2cd671d5bf6541ce50f7cba8a76ad6

@nathanchance nathanchance added [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle and removed [PATCH] Accepted A submitted patch has been accepted upstream labels Nov 10, 2023
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-Wc23-extensions [BUG] linux A bug that should be fixed in the mainline kernel. [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle
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