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authorKuniyuki Iwashima <kuniyu@amazon.com>2022-07-11 17:15:19 -0700
committerDavid S. Miller <davem@davemloft.net>2022-07-13 12:56:48 +0100
commit7dee5d7747a69aa2be41f04c6a7ecfe3ac8cdf18 (patch)
tree64ff9ebba3025277b0b6f29b75143aa8ce0c5148
parent22b9c41a3fb8ef4624bcda312665937d2ba98aa7 (diff)
sysctl: Fix data-races in proc_dou8vec_minmax().
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_dou8vec_minmax() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_dou8vec_minmax() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side. Fixes: cb9444130662 ("sysctl: add proc_dou8vec_minmax()") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--kernel/sysctl.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index bf9383d17e1b..b016d68da08a 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1007,13 +1007,13 @@ int proc_dou8vec_minmax(struct ctl_table *table, int write,
tmp.maxlen = sizeof(val);
tmp.data = &val;
- val = *data;
+ val = READ_ONCE(*data);
res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos,
do_proc_douintvec_minmax_conv, &param);
if (res)
return res;
if (write)
- *data = val;
+ WRITE_ONCE(*data, val);
return 0;
}
EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);