From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Sven Schnelle <svens@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 16/28] s390/ftrace: save traced function caller
Date: Fri, 5 Jun 2020 16:15:18 +0200 [thread overview]
Message-ID: <20200605140253.342375848@linuxfoundation.org> (raw)
In-Reply-To: <20200605140252.338635395@linuxfoundation.org>
From: Vasily Gorbik <gor@linux.ibm.com>
[ Upstream commit b4adfe55915d8363e244e42386d69567db1719b9 ]
A typical backtrace acquired from ftraced function currently looks like
the following (e.g. for "path_openat"):
arch_stack_walk+0x15c/0x2d8
stack_trace_save+0x50/0x68
stack_trace_call+0x15a/0x3b8
ftrace_graph_caller+0x0/0x1c
0x3e0007e3c98 <- ftraced function caller (should be do_filp_open+0x7c/0xe8)
do_open_execat+0x70/0x1b8
__do_execve_file.isra.0+0x7d8/0x860
__s390x_sys_execve+0x56/0x68
system_call+0xdc/0x2d8
Note random "0x3e0007e3c98" stack value as ftraced function caller. This
value causes either imprecise unwinder result or unwinding failure.
That "0x3e0007e3c98" comes from r14 of ftraced function stack frame, which
it haven't had a chance to initialize since the very first instruction
calls ftrace code ("ftrace_caller"). (ftraced function might never
save r14 as well). Nevertheless according to s390 ABI any function
is called with stack frame allocated for it and r14 contains return
address. "ftrace_caller" itself is called with "brasl %r0,ftrace_caller".
So, to fix this issue simply always save traced function caller onto
ftraced function stack frame.
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/kernel/mcount.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
index 83afd5b78e16..020f9aac7dc0 100644
--- a/arch/s390/kernel/mcount.S
+++ b/arch/s390/kernel/mcount.S
@@ -40,6 +40,7 @@ EXPORT_SYMBOL(_mcount)
ENTRY(ftrace_caller)
.globl ftrace_regs_caller
.set ftrace_regs_caller,ftrace_caller
+ stg %r14,(__SF_GPRS+8*8)(%r15) # save traced function caller
lgr %r1,%r15
#if !(defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT))
aghi %r0,MCOUNT_RETURN_FIXUP
--
2.25.1
next prev parent reply other threads:[~2020-06-05 14:20 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-05 14:15 [PATCH 4.19 00/28] 4.19.127-rc1 review Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 01/28] Revert "cgroup: Add memory barriers to plug cgroup_rstat_updated() race window" Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 02/28] libnvdimm: Fix endian conversion issues Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 03/28] mm: Fix mremap not considering huge pmd devmap Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 04/28] HID: sony: Fix for broken buttons on DS3 USB dongles Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 05/28] HID: i2c-hid: add Schneider SCL142ALM to descriptor override Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 06/28] p54usb: add AirVasT USB stick device-id Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 07/28] kernel/relay.c: handle alloc_percpu returning NULL in relay_open Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 08/28] mmc: fix compilation of user API Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 09/28] scsi: ufs: Release clock if DMA map fails Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 10/28] net: dsa: mt7530: set CPU port to fallback mode Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 11/28] airo: Fix read overflows sending packets Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 12/28] drm/i915: fix port checks for MST support on gen >= 11 Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 13/28] scsi: hisi_sas: Check sas_port before using it Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 14/28] powerpc/powernv: Avoid re-registration of imc debugfs directory Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 15/28] spi: dw: use "smp_mb()" to avoid sending spi data error Greg Kroah-Hartman
2020-06-07 20:09 ` Pavel Machek
2020-06-08 11:16 ` Mark Brown
2020-06-10 15:01 ` Pavel Machek
2020-06-05 14:15 ` Greg Kroah-Hartman [this message]
2020-06-05 14:15 ` [PATCH 4.19 17/28] ARC: Fix ICCM & DCCM runtime size checks Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 18/28] ARC: [plat-eznps]: Restrict to CONFIG_ISA_ARCOMPACT Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 19/28] evm: Fix RCU list related warnings Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 20/28] i2c: altera: Fix race between xfer_msg and isr thread Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 21/28] x86/mmiotrace: Use cpumask_available() for cpumask_var_t variables Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 22/28] net: bmac: Fix read of MAC address from ROM Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 23/28] drm/edid: Add Oculus Rift S to non-desktop list Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 24/28] s390/mm: fix set_huge_pte_at() for empty ptes Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 25/28] null_blk: return error for invalid zone size Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 26/28] net/ethernet/freescale: rework quiesce/activate for ucc_geth Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 27/28] net: ethernet: stmmac: Enable interface clocks on probe for IPQ806x Greg Kroah-Hartman
2020-06-05 14:15 ` [PATCH 4.19 28/28] net: smsc911x: Fix runtime PM imbalance on error Greg Kroah-Hartman
2020-06-05 22:19 ` [PATCH 4.19 00/28] 4.19.127-rc1 review Shuah Khan
2020-06-06 6:32 ` Jon Hunter
2020-06-07 11:19 ` Greg Kroah-Hartman
2020-06-06 13:33 ` Guenter Roeck
2020-06-07 5:44 ` Naresh Kamboju
2020-06-08 9:44 ` Chris Paterson
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