Patch "lib/vsprintf: Remove atomic-unsafe support for %pCr" has been added to the 4.17-stable tree

Commit Message

Greg KH July 1, 2018, 9:01 a.m. UTC

This is a note to let you know that I've just added the patch titled

    lib/vsprintf: Remove atomic-unsafe support for %pCr

to the 4.17-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     lib-vsprintf-remove-atomic-unsafe-support-for-pcr.patch
and it can be found in the queue-4.17 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[e-mail]> know about it.


From 666902e42fd8344b923c02dc5b0f37948ff4f225 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <[e-mail]>
Date: Fri, 1 Jun 2018 11:28:22 +0200
Subject: lib/vsprintf: Remove atomic-unsafe support for %pCr

From: Geert Uytterhoeven <[e-mail]>

commit 666902e42fd8344b923c02dc5b0f37948ff4f225 upstream.

"%pCr" formats the current rate of a clock, and calls clk_get_rate().
The latter obtains a mutex, hence it must not be called from atomic
context.

Remove support for this rarely-used format, as vsprintf() (and e.g.
printk()) must be callable from any context.

Any remaining out-of-tree users will start seeing the clock's name
printed instead of its rate.

Reported-by: Jia-Ju Bai <[e-mail]>
Fixes: 900cca2944254edd ("lib/vsprintf: add %pC{,n,r} format specifiers for clocks")
Link: http://lkml.kernel.org/r/[e-mail]
To: Jia-Ju Bai <[e-mail]>
To: Jonathan Corbet <[e-mail]>
To: Michael Turquette <[e-mail]>
To: Stephen Boyd <[e-mail]>
To: Zhang Rui <[e-mail]>
To: Eduardo Valentin <[e-mail]>
To: Eric Anholt <[e-mail]>
To: Stefan Wahren <[e-mail]>
To: Greg Kroah-Hartman <[e-mail]>
Cc: Sergey Senozhatsky <[e-mail]>
Cc: Petr Mladek <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: Geert Uytterhoeven <[e-mail]>
Cc: [e-mail] # 4.1+
Signed-off-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Petr Mladek <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

---
 Documentation/core-api/printk-formats.rst |    3 +--
 lib/vsprintf.c                            |    3 ---
 2 files changed, 1 insertion(+), 5 deletions(-)



Patches currently in stable-queue which might be from [e-mail] are

queue-4.17/lib-vsprintf-remove-atomic-unsafe-support-for-pcr.patch
queue-4.17/thermal-bcm2835-stop-using-printk-format-pcr.patch
queue-4.17/serial-sh-sci-use-spin_-try-lock_irqsave-instead-of-open-coding-version.patch
queue-4.17/clk-renesas-cpg-mssr-stop-using-printk-format-pcr.patch

Patch

--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -419,11 +419,10 @@  struct clk
 
 	%pC	pll1
 	%pCn	pll1
-	%pCr	1560000000
 
 For printing struct clk structures. %pC and %pCn print the name
 (Common Clock Framework) or address (legacy clock framework) of the
-structure; %pCr prints the current clock rate.
+structure.
 
 Passed by reference.
 
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1456,9 +1456,6 @@  char *clock(char *buf, char *end, struct
 		return string(buf, end, NULL, spec);
 
 	switch (fmt[1]) {
-	case 'r':
-		return number(buf, end, clk_get_rate(clk), spec);
-
 	case 'n':
 	default:
 #ifdef CONFIG_COMMON_CLK