FAILED: patch "[PATCH] printk: fix possible reuse of va_list variable" failed to apply to 4.9-stable tree
The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 988a35f8da1dec5a8cd2788054d1e717be61bf25 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Date: Fri, 11 May 2018 19:54:19 +0900 Subject: [PATCH] printk: fix possible reuse of va_list variable
I noticed that there is a possibility that printk_safe_log_store() causes kernel oops because "args" parameter is passed to vsnprintf() again when atomic_cmpxchg() detected that we raced. Fix this by using va_copy().
Link: http://lkml.kernel.org/r/201805112002.GIF21216.OFVHFOMLJtQFSO@I-love.SAKURA.... Cc: Peter Zijlstra peterz@infradead.org Cc: Steven Rostedt rostedt@goodmis.org Cc: dvyukov@google.com Cc: syzkaller@googlegroups.com Cc: fengguang.wu@intel.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Fixes: 42a0bb3f71383b45 ("printk/nmi: generic solution for safe printk in NMI") Cc: 4.7+ stable@vger.kernel.org # v4.7+ Reviewed-by: Sergey Senozhatsky sergey.senozhatsky@gmail.com Signed-off-by: Petr Mladek pmladek@suse.com
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index 3e3c2004bb23..449d67edfa4b 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -82,6 +82,7 @@ static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s, { int add; size_t len; + va_list ap;
again: len = atomic_read(&s->len); @@ -100,7 +101,9 @@ static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s, if (!len) smp_rmb();
- add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, args); + va_copy(ap, args); + add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, ap); + va_end(ap); if (!add) return 0;
On 2018/07/01 18:19, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
OK. Filename and function name are different as of 4.9. Updated patch for 4.9-stable is attached below.
From 030b03ee5602e045398d8452afdcd136f3f5272c Mon Sep 17 00:00:00 2001
From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Date: Sun, 1 Jul 2018 19:34:37 +0900 Subject: [PATCH] printk: fix possible reuse of va_list variable
commit 988a35f8da1dec5a8cd2788054d1e717be61bf25 upstream.
I noticed that there is a possibility that printk_safe_log_store() causes kernel oops because "args" parameter is passed to vsnprintf() again when atomic_cmpxchg() detected that we raced. Fix this by using va_copy().
Link: http://lkml.kernel.org/r/201805112002.GIF21216.OFVHFOMLJtQFSO@I-love.SAKURA.... Cc: Peter Zijlstra peterz@infradead.org Cc: Steven Rostedt rostedt@goodmis.org Cc: dvyukov@google.com Cc: syzkaller@googlegroups.com Cc: fengguang.wu@intel.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Fixes: 42a0bb3f71383b45 ("printk/nmi: generic solution for safe printk in NMI") Cc: 4.7+ stable@vger.kernel.org # v4.7+ Reviewed-by: Sergey Senozhatsky sergey.senozhatsky@gmail.com Signed-off-by: Petr Mladek pmladek@suse.com --- kernel/printk/nmi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/printk/nmi.c b/kernel/printk/nmi.c index 16bab47..5fa65aa 100644 --- a/kernel/printk/nmi.c +++ b/kernel/printk/nmi.c @@ -63,6 +63,7 @@ static int vprintk_nmi(const char *fmt, va_list args) struct nmi_seq_buf *s = this_cpu_ptr(&nmi_print_seq); int add = 0; size_t len; + va_list ap;
again: len = atomic_read(&s->len); @@ -79,7 +80,9 @@ static int vprintk_nmi(const char *fmt, va_list args) if (!len) smp_rmb();
- add = vsnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, args); + va_copy(ap, args); + add = vsnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, ap); + va_end(ap);
/* * Do it once again if the buffer has been flushed in the meantime.
On (07/01/18 19:41), Tetsuo Handa wrote:
On 2018/07/01 18:19, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
OK. Filename and function name are different as of 4.9. Updated patch for 4.9-stable is attached below.
Thanks!
-ss
On Sun, Jul 01, 2018 at 07:41:54PM +0900, Tetsuo Handa wrote:
On 2018/07/01 18:19, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
OK. Filename and function name are different as of 4.9. Updated patch for 4.9-stable is attached below.
Thanks, now queued up.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
gregkh＠linuxfoundation.org
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Sergey Senozhatsky -
Tetsuo Handa