diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-07-11 17:15:20 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-07-13 12:56:49 +0100 |
| commit | 7d1025e559782b58824b36cb8ad547a69f2e4b31 (patch) | |
| tree | f6b3b3bb5f284a05494be81877eadaf0d7ab68a5 /kernel/sysctl.c | |
| parent | 7dee5d7747a69aa2be41f04c6a7ecfe3ac8cdf18 (diff) | |
| download | lwn-7d1025e559782b58824b36cb8ad547a69f2e4b31.tar.gz lwn-7d1025e559782b58824b36cb8ad547a69f2e4b31.zip | |
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.c | 8 |
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. |