From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>
Subject: [PATCH 4.9 18/21] powerpc/kprobe: Fix oops when kprobed on stdu instruction
Date: Tue, 25 Apr 2017 16:09:13 +0100 [thread overview]
Message-ID: <20170425150828.246723226@linuxfoundation.org> (raw)
In-Reply-To: <20170425150827.381333941@linuxfoundation.org>
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
commit 9e1ba4f27f018742a1aa95d11e35106feba08ec1 upstream.
If we set a kprobe on a 'stdu' instruction on powerpc64, we see a kernel
OOPS:
Bad kernel stack pointer cd93c840 at c000000000009868
Oops: Bad kernel stack pointer, sig: 6 [#1]
...
GPR00: c000001fcd93cb30 00000000cd93c840 c0000000015c5e00 00000000cd93c840
...
NIP [c000000000009868] resume_kernel+0x2c/0x58
LR [c000000000006208] program_check_common+0x108/0x180
On a 64-bit system when the user probes on a 'stdu' instruction, the kernel does
not emulate actual store in emulate_step() because it may corrupt the exception
frame. So the kernel does the actual store operation in exception return code
i.e. resume_kernel().
resume_kernel() loads the saved stack pointer from memory using lwz, which only
loads the low 32-bits of the address, causing the kernel crash.
Fix this by loading the 64-bit value instead.
Fixes: be96f63375a1 ("powerpc: Split out instruction analysis part of emulate_step()")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
[mpe: Change log massage, add stable tag]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/kernel/entry_64.S | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -689,7 +689,7 @@ resume_kernel:
addi r8,r1,INT_FRAME_SIZE /* Get the kprobed function entry */
- lwz r3,GPR1(r1)
+ ld r3,GPR1(r1)
subi r3,r3,INT_FRAME_SIZE /* dst: Allocate a trampoline exception frame */
mr r4,r1 /* src: current exception frame */
mr r1,r3 /* Reroute the trampoline frame to r1 */
@@ -703,8 +703,8 @@ resume_kernel:
addi r6,r6,8
bdnz 2b
- /* Do real store operation to complete stwu */
- lwz r5,GPR1(r1)
+ /* Do real store operation to complete stdu */
+ ld r5,GPR1(r1)
std r8,0(r5)
/* Clear _TIF_EMULATE_STACK_STORE flag */
next prev parent reply other threads:[~2017-04-25 15:12 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-25 15:08 [PATCH 4.9 00/21] 4.9.25-stable review Greg Kroah-Hartman
2017-04-25 15:08 ` [PATCH 4.9 01/21] KEYS: Disallow keyrings beginning with . to be joined as session keyrings Greg Kroah-Hartman
2017-04-25 15:08 ` [PATCH 4.9 02/21] KEYS: Change the name of the dead type to ".dead" to prevent user access Greg Kroah-Hartman
2017-04-25 15:08 ` [PATCH 4.9 03/21] KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings Greg Kroah-Hartman
2017-04-25 15:08 ` [PATCH 4.9 04/21] tracing: Allocate the snapshot buffer before enabling probe Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 05/21] ring-buffer: Have ring_buffer_iter_empty() return true when empty Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 06/21] mm: prevent NR_ISOLATE_* stats from going negative Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 07/21] cifs: Do not send echoes before Negotiate is complete Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 08/21] CIFS: remove bad_network_name flag Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 09/21] s390/mm: fix CMMA vs KSM vs others Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 10/21] Input: elantech - add Fujitsu Lifebook E547 to force crc_enabled Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 11/21] ACPI / power: Avoid maybe-uninitialized warning Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 12/21] mmc: sdhci-esdhc-imx: increase the pad I/O drive strength for DDR50 card Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 13/21] ubifs: Fix RENAME_WHITEOUT support Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 14/21] ubifs: Fix O_TMPFILE corner case in ubifs_link() Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 15/21] mac80211: reject ToDS broadcast data frames Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 16/21] mac80211: fix MU-MIMO follow-MAC mode Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 17/21] ubi/upd: Always flush after prepared for an update Greg Kroah-Hartman
2017-04-25 15:09 ` Greg Kroah-Hartman [this message]
2017-04-25 15:09 ` [PATCH 4.9 19/21] x86/mce/AMD: Give a name to MCA bank 3 when accessed with legacy MSRs Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 20/21] x86/mce: Make the MCE notifier a blocking one Greg Kroah-Hartman
2017-04-25 15:09 ` [PATCH 4.9 21/21] device-dax: switch to srcu, fix rcu_read_lock() vs pte allocation Greg Kroah-Hartman
2017-04-25 18:24 ` [PATCH 4.9 00/21] 4.9.25-stable review Shuah Khan
2017-04-26 2:23 ` Guenter Roeck
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