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Groups > linux.kernel > #1591515

[PATCH 18/26] [media] i2c: cx25840: avoid stack overflow with KASAN

From Arnd Bergmann <arnd@arndb.de>
Newsgroups linux.kernel
Subject [PATCH 18/26] [media] i2c: cx25840: avoid stack overflow with KASAN
Date 2017-03-02 23:30 +0100
Message-ID <tgHot-hN-7@gated-at.bofh.it> (permalink)
References <tgCf7-56J-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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With CONFIG_KASAN, this driver has shown a ridiculously large stack frame
in one configuration:

drivers/media/i2c/cx25840/cx25840-core.c:4960:1: error: the frame size of 94000 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]

In most builds, it's only about 3300 bytes, but that's still large anough to
risk a kernel stack overflow.

Marking the two register access functions as noinline_for_kasan avoids
the problem and brings the largest stack frame size down to 232 bytes.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/media/i2c/cx25840/cx25840-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/cx25840/cx25840-core.c b/drivers/media/i2c/cx25840/cx25840-core.c
index b8d3c070bfc1..fd72e5a11cb9 100644
--- a/drivers/media/i2c/cx25840/cx25840-core.c
+++ b/drivers/media/i2c/cx25840/cx25840-core.c
@@ -81,7 +81,7 @@ MODULE_PARM_DESC(debug, "Debugging messages [0=Off (default) 1=On]");
 /* ----------------------------------------------------------------------- */
 static void cx23888_std_setup(struct i2c_client *client);
 
-int cx25840_write(struct i2c_client *client, u16 addr, u8 value)
+noinline_for_kasan int cx25840_write(struct i2c_client *client, u16 addr, u8 value)
 {
 	u8 buffer[3];
 	buffer[0] = addr >> 8;
@@ -90,7 +90,7 @@ int cx25840_write(struct i2c_client *client, u16 addr, u8 value)
 	return i2c_master_send(client, buffer, 3);
 }
 
-int cx25840_write4(struct i2c_client *client, u16 addr, u32 value)
+noinline_for_kasan int cx25840_write4(struct i2c_client *client, u16 addr, u32 value)
 {
 	u8 buffer[6];
 	buffer[0] = addr >> 8;
-- 
2.9.0

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Thread

[PATCH 00/26] bring back stack frame warning with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
  [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
    Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-06 10:50 +0100
      Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-06 12:00 +0100
        Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-06 12:20 +0100
          Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-06 12:20 +0100
            Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-06 12:40 +0100
  [PATCH 15/26] [media] tuners: i2c: reduce stack usage for tuner_i2c_xfer_* Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
  [PATCH 11/26] rtlwifi: reduce stack usage for KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
  [PATCH 04/26] tty: kbd: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
  [PATCH 12/26] wl3501_cs: reduce stack size for KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
  [PATCH 09/26] brcmsmac: split up wlc_phy_workarounds_nphy Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
    Re: [PATCH 09/26] brcmsmac: split up wlc_phy_workarounds_nphy Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-06 10:40 +0100
  [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
    Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Alexander Potapenko <glider@google.com> - 2017-03-03 15:00 +0100
      Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Alexander Potapenko <glider@google.com> - 2017-03-03 15:40 +0100
        Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Arnd Bergmann <arnd@arndb.de> - 2017-03-03 16:10 +0100
      Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Arnd Bergmann <arnd@arndb.de> - 2017-03-03 15:40 +0100
    RE: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation David Laight <David.Laight@ACULAB.COM> - 2017-03-03 18:10 +0100
  [PATCH 05/26] netlink: mark nla_put_{u8,u16,u32} noinline_for_kasan Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
  [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
    Re: [PATCH 08/26] brcmsmac: make some local variables 'static const'  to reduce stack size Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-06 10:40 +0100
      Re: [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Kalle Valo <kvalo@codeaurora.org> - 2017-03-06 17:40 +0100
        Re: [PATCH 08/26] brcmsmac: make some local variables 'static const'  to reduce stack size Arnd Bergmann <arnd@arndb.de> - 2017-03-06 22:40 +0100
          Re: [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Kalle Valo <kvalo@codeaurora.org> - 2017-03-07 10:50 +0100
            Re: [PATCH 08/26] brcmsmac: make some local variables 'static const'  to reduce stack size Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-07 11:10 +0100
  [PATCH 22/26] drm/i915/gvt: don't overflow the kernel stack with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:40 +0100
  Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Joe Perches <joe@perches.com> - 2017-03-02 19:00 +0100
    Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Joe Perches <joe@perches.com> - 2017-03-02 23:50 +0100
      Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-03 00:10 +0100
        Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Joe Perches <joe@perches.com> - 2017-03-03 01:00 +0100
    Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-03 00:00 +0100
  [PATCH 24/26] ocfs2: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 20:10 +0100
  [PATCH 23/26] mtd: cfi: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 20:20 +0100
  [PATCH 18/26] [media] i2c: cx25840: avoid stack overflow with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 23:30 +0100
  Re: [PATCH 00/26] bring back stack frame warning with KASAN Alexander Potapenko <glider@google.com> - 2017-03-03 13:30 +0100
    Re: [PATCH 00/26] bring back stack frame warning with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-03 14:00 +0100
  Re: [PATCH 10/26] brcmsmac: reindent split functions Kalle Valo <kvalo@codeaurora.org> - 2017-03-06 17:50 +0100

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