From: Andrey Vagin <[email protected]>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 1195d94e006b23c6292e78857e154872e33b6d7e upstream.
proc_dointvec_minmax() returns zero if a new value has been set. So we
don't need to check all charecters have been handled.
Below you can find two examples. In the new value has not been handled
properly.
$ strace ./a.out
open("/proc/sys/kernel/auto_msgmni", O_WRONLY) = 3
write(3, "0\n\0", 3) = 2
close(3) = 0
exit_group(0)
$ cat /sys/kernel/debug/tracing/trace
$strace ./a.out
open("/proc/sys/kernel/auto_msgmni", O_WRONLY) = 3
write(3, "0\n", 2) = 2
close(3) = 0
$ cat /sys/kernel/debug/tracing/trace
a.out-697 [000] .... 3280.998235: unregister_ipcns_notifier
<-proc_ipcauto_dointvec_minmax
Fixes: 9eefe520c814 ("ipc: do not use a negative value to re-enable msgmni
automatic recomputin")
Signed-off-by: Andrey Vagin <[email protected]>
Cc: Mathias Krause <[email protected]>
Cc: Manfred Spraul <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
---
ipc/ipc_sysctl.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index b0e99deb6d05..a0f0ab2ac2a8 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -123,7 +123,6 @@ static int proc_ipcauto_dointvec_minmax(ctl_table *table,
int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table ipc_table;
- size_t lenp_bef = *lenp;
int oldval;
int rc;
@@ -133,7 +132,7 @@ static int proc_ipcauto_dointvec_minmax(ctl_table *table,
int write,
rc = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
- if (write && !rc && lenp_bef == *lenp) {
+ if (write && !rc) {
int newval = *((int *)(ipc_table.data));
/*
* The file "auto_msgmni" has correctly been set.
--
2.1.3
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