5.10-stable patches

added patches:
	sysctl-fix-data-races-in-proc_dou8vec_minmax.patch

diff --git a/queue-5.10/series b/queue-5.10/series
index 24702d5c9461f20c372d1c9cb313c061fd6d5c8e..bbb555096bd66716b5254636a595ac1cfff8057e 100644 (file)
--- a/queue-5.10/series
+++ b/queue-5.10/series
@@ -121,3 +121,4 @@ riscv-handle-zicsr-zifencei-issues-between-clang-and-binutils.patch
 kexec-move-locking-into-do_kexec_load.patch
 kexec-turn-all-kexec_mutex-acquisitions-into-trylocks.patch
 panic-kexec-make-__crash_kexec-nmi-safe.patch
+sysctl-fix-data-races-in-proc_dou8vec_minmax.patch

diff --git a/queue-5.10/sysctl-fix-data-races-in-proc_dou8vec_minmax.patch b/queue-5.10/sysctl-fix-data-races-in-proc_dou8vec_minmax.patch
new file mode 100644 (file)
index 0000000..d3502ad
--- /dev/null
+++ b/queue-5.10/sysctl-fix-data-races-in-proc_dou8vec_minmax.patch
@@ -0,0 +1,44 @@
+From 7dee5d7747a69aa2be41f04c6a7ecfe3ac8cdf18 Mon Sep 17 00:00:00 2001
+From: Kuniyuki Iwashima <kuniyu@amazon.com>
+Date: Mon, 11 Jul 2022 17:15:19 -0700
+Subject: sysctl: Fix data-races in proc_dou8vec_minmax().
+
+From: Kuniyuki Iwashima <kuniyu@amazon.com>
+
+commit 7dee5d7747a69aa2be41f04c6a7ecfe3ac8cdf18 upstream.
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ kernel/sysctl.c |    4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/kernel/sysctl.c
++++ b/kernel/sysctl.c
+@@ -1109,13 +1109,13 @@ int proc_dou8vec_minmax(struct ctl_table
+ 
+       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);