diff mbox series

[v2,net-next] tcp: fix signed/unsigned comparison

Message ID 20220417183432.3952871-1-eric.dumazet@gmail.com (mailing list archive)
State Accepted
Commit 843f77407eebee07c2a3300df0c4b33f64322e29
Delegated to: Netdev Maintainers
Headers show
Series [v2,net-next] tcp: fix signed/unsigned comparison | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/cc_maintainers warning 2 maintainers not CCed: yoshfuji@linux-ipv6.org dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 3 this patch: 3
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 12 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet April 17, 2022, 6:34 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

Kernel test robot reported:

smatch warnings:
net/ipv4/tcp_input.c:5966 tcp_rcv_established() warn: unsigned 'reason' is never less than zero.

I actually had one packetdrill failing because of this bug,
and was about to send the fix :)

v2: Andreas Schwab also pointed out that @reason needs to be negated
    before we reach tcp_drop_reason()

Fixes: 4b506af9c5b8 ("tcp: add two drop reasons for tcp_ack()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Andreas Schwab <schwab@linux-m68k.org>
---
 net/ipv4/tcp_input.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org April 18, 2022, 9:30 a.m. UTC | #1 
Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Sun, 17 Apr 2022 11:34:32 -0700 you wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> Kernel test robot reported:
> 
> smatch warnings:
> net/ipv4/tcp_input.c:5966 tcp_rcv_established() warn: unsigned 'reason' is never less than zero.
> 
> [...]

Here is the summary with links:
  - [v2,net-next] tcp: fix signed/unsigned comparison
    https://git.kernel.org/netdev/net-next/c/843f77407eeb

You are awesome, thank you!
diff mbox series

Patch

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index cf2dc19bb8c766c1d33406053fd61c0873f15489..daff631b94865ae95cbd49ed8ecf6782edaf16e7 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5959,9 +5959,10 @@  void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
 
 step5:
 	reason = tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT);
-	if (reason < 0)
+	if ((int)reason < 0) {
+		reason = -reason;
 		goto discard;
-
+	}
 	tcp_rcv_rtt_measure_ts(sk, skb);
 
 	/* Process urgent data. */