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tcp: Suppress knownConditionTrueFalse cppcheck false positive

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cppcheck 2.10 reports:

tcp.c:1815:12: style: Condition 'wnd>prev_scaled' is always false [knownConditionTrueFalse]
  if ((wnd > prev_scaled && wnd * 99 / 100 < prev_scaled) ||
           ^
tcp.c:1808:8: note: Assignment 'wnd=((1<<(16+8))<(wnd))?(1<<(16+8)):(wnd)', assigned value is less than 1
 wnd = MIN(MAX_WINDOW, wnd);
       ^
tcp.c:1811:19: note: Assuming condition is false
  if (prev_scaled == wnd)
                  ^
tcp.c:1815:12: note: Condition 'wnd>prev_scaled' is always false
  if ((wnd > prev_scaled && wnd * 99 / 100 < prev_scaled) ||
           ^

but this is not actually the case: wnd is typically greater than 1,
and might very well be greater than prev_scaled as well.

I bisected this down to cppcheck commit b4d455df487c ("Fix 11349: FP
negativeIndex for clamped array index (#4627)") and reported findings
at https://github.com/danmar/cppcheck/pull/4627.

Suppress the warning for the moment being.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2023-02-25 12:09:01 +01:00
parent 834b9a3049
commit da46fdac36
1 changed files with 9 additions and 0 deletions
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9
tcp.c
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@ -1812,6 +1812,15 @@ static void tcp_clamp_window(const struct ctx *c, struct tcp_tap_conn *conn,
return;
/* Discard +/- 1% updates to spare some syscalls. */
/* TODO: cppcheck, starting from commit b4d455df487c ("Fix
* 11349: FP negativeIndex for clamped array index (#4627)"),
* reports wnd > prev_scaled as always being true, see also:
*
* https://github.com/danmar/cppcheck/pull/4627
*
* drop this suppression once that's resolved.
*/
/* cppcheck-suppress knownConditionTrueFalse */
if ((wnd > prev_scaled && wnd * 99 / 100 < prev_scaled) ||
(wnd < prev_scaled && wnd * 101 / 100 > prev_scaled))
return;