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authorKuniyuki Iwashima <kuniyu@amazon.com>2022-07-12 03:15:20 +0300
committerDavid S. Miller <davem@davemloft.net>2022-07-13 14:56:49 +0300
commit7d1025e559782b58824b36cb8ad547a69f2e4b31 (patch)
treef6b3b3bb5f284a05494be81877eadaf0d7ab68a5 /kernel/sysctl.c
parent7dee5d7747a69aa2be41f04c6a7ecfe3ac8cdf18 (diff)
downloadlinux-7d1025e559782b58824b36cb8ad547a69f2e4b31.tar.xz
sysctl: Fix data-races in proc_dointvec_ms_jiffies().
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_ms_jiffies() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_dointvec_ms_jiffies() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/sysctl.c')
-rw-r--r--kernel/sysctl.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b016d68da08a..d99bc3945445 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1224,9 +1224,9 @@ static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
if (jif > INT_MAX)
return 1;
- *valp = (int)jif;
+ WRITE_ONCE(*valp, (int)jif);
} else {
- int val = *valp;
+ int val = READ_ONCE(*valp);
unsigned long lval;
if (val < 0) {
*negp = true;
@@ -1294,8 +1294,8 @@ int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
* @ppos: the current position in the file
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
- * values from/to the user buffer, treated as an ASCII string.
- * The values read are assumed to be in 1/1000 seconds, and
+ * values from/to the user buffer, treated as an ASCII string.
+ * The values read are assumed to be in 1/1000 seconds, and
* are converted into jiffies.
*
* Returns 0 on success.