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sysctl: Fix data races in proc_dointvec_jiffies().
[ Upstream commite877820877
] A sysctl variable is accessed concurrently, and there is always a chance of data-race. So, all readers and writers need some basic protection to avoid load/store-tearing. This patch changes proc_dointvec_jiffies() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_dointvec_jiffies() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side. Fixes:1da177e4c3
("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
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1 changed files with 5 additions and 2 deletions
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@ -1245,9 +1245,12 @@ static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
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if (write) {
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if (*lvalp > INT_MAX / HZ)
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return 1;
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*valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
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if (*negp)
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WRITE_ONCE(*valp, -*lvalp * HZ);
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else
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WRITE_ONCE(*valp, *lvalp * HZ);
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} else {
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int val = *valp;
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int val = READ_ONCE(*valp);
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unsigned long lval;
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if (val < 0) {
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*negp = true;
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