Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
tcp: annotate data races in __tcp_oow_rate_limited()
request sockets are lockless, __tcp_oow_rate_limited() could be called
on the same object from different cpus. This is harmless.
Add READ_ONCE()/WRITE_ONCE() annotations to avoid a KCSAN report.
Fixes: 4ce7e93cb3fe ("tcp: rate limit ACK sent by SYN_RECV request sockets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
authored by
Eric Dumazet
and committed by
David S. Miller
998127cd
c94683ed
+9
-3
+9
-3
net/ipv4/tcp_input.c
+9
-3
net/ipv4/tcp_input.c
···
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static bool __tcp_oow_rate_limited(struct net *net, int mib_idx,
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u32 *last_oow_ack_time)
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{
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-
if (*last_oow_ack_time) {
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-
s32 elapsed = (s32)(tcp_jiffies32 - *last_oow_ack_time);
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+
/* Paired with the WRITE_ONCE() in this function. */
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u32 val = READ_ONCE(*last_oow_ack_time);
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+
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if (val) {
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s32 elapsed = (s32)(tcp_jiffies32 - val);
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if (0 <= elapsed &&
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elapsed < READ_ONCE(net->ipv4.sysctl_tcp_invalid_ratelimit)) {
···
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}
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}
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-
*last_oow_ack_time = tcp_jiffies32;
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+
/* Paired with the prior READ_ONCE() and with itself,
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* as we might be lockless.
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*/
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+
WRITE_ONCE(*last_oow_ack_time, tcp_jiffies32);
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return false; /* not rate-limited: go ahead, send dupack now! */
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}