| Message ID | 20220706234003.66760-3-kuniyu@amazon.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 4762b532ec9539755aab61445d5da6e1926ccb99 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | sysctl: Fix data-races around ipv4_table. | expand |
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c8a05655ae60..2ab8c2a37e8f 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -472,9 +472,9 @@ static int do_proc_douintvec_conv(unsigned long *lvalp, if (write) { if (*lvalp > UINT_MAX) return -EINVAL; - *valp = *lvalp; + WRITE_ONCE(*valp, *lvalp); } else { - unsigned int val = *valp; + unsigned int val = READ_ONCE(*valp); *lvalp = (unsigned long)val; } return 0;
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_douintvec() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_douintvec() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side. Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> --- CC: Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com> --- kernel/sysctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)