Messages in this thread Patch in this message | | | From | Kuniyuki Iwashima <> | Subject | [PATCH v2 net 02/12] sysctl: Fix data races in proc_douintvec(). | Date | Wed, 6 Jul 2022 16:39:53 -0700 |
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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(-)
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; -- 2.30.2
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