From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Russell King <rmk+kernel@armlinux.org.uk>,
Jing Xiangfeng <jingxiangfeng@huawei.com>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.4 05/13] ARM: mm: fix alignment handler faults under memory pressure
Date: Wed, 30 Oct 2019 11:57:43 -0400 [thread overview]
Message-ID: <20191030155751.10960-5-sashal@kernel.org> (raw)
In-Reply-To: <20191030155751.10960-1-sashal@kernel.org>
From: Russell King <rmk+kernel@armlinux.org.uk>
[ Upstream commit 67e15fa5b487adb9b78a92789eeff2d6ec8f5cee ]
When the system has high memory pressure, the page containing the
instruction may be paged out. Using probe_kernel_address() means that
if the page is swapped out, the resulting page fault will not be
handled because page faults are disabled by this function.
Use get_user() to read the instruction instead.
Reported-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Fixes: b255188f90e2 ("ARM: fix scheduling while atomic warning in alignment handling code")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/mm/alignment.c | 44 +++++++++++++++++++++++++++++++++--------
1 file changed, 36 insertions(+), 8 deletions(-)
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
index 7d5f4c736a16b..cd18eda014c24 100644
--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c
@@ -767,6 +767,36 @@ do_alignment_t32_to_handler(unsigned long *pinstr, struct pt_regs *regs,
return NULL;
}
+static int alignment_get_arm(struct pt_regs *regs, u32 *ip, unsigned long *inst)
+{
+ u32 instr = 0;
+ int fault;
+
+ if (user_mode(regs))
+ fault = get_user(instr, ip);
+ else
+ fault = probe_kernel_address(ip, instr);
+
+ *inst = __mem_to_opcode_arm(instr);
+
+ return fault;
+}
+
+static int alignment_get_thumb(struct pt_regs *regs, u16 *ip, u16 *inst)
+{
+ u16 instr = 0;
+ int fault;
+
+ if (user_mode(regs))
+ fault = get_user(instr, ip);
+ else
+ fault = probe_kernel_address(ip, instr);
+
+ *inst = __mem_to_opcode_thumb16(instr);
+
+ return fault;
+}
+
static int
do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
@@ -774,10 +804,10 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
unsigned long instr = 0, instrptr;
int (*handler)(unsigned long addr, unsigned long instr, struct pt_regs *regs);
unsigned int type;
- unsigned int fault;
u16 tinstr = 0;
int isize = 4;
int thumb2_32b = 0;
+ int fault;
if (interrupts_enabled(regs))
local_irq_enable();
@@ -786,15 +816,14 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
if (thumb_mode(regs)) {
u16 *ptr = (u16 *)(instrptr & ~1);
- fault = probe_kernel_address(ptr, tinstr);
- tinstr = __mem_to_opcode_thumb16(tinstr);
+
+ fault = alignment_get_thumb(regs, ptr, &tinstr);
if (!fault) {
if (cpu_architecture() >= CPU_ARCH_ARMv7 &&
IS_T32(tinstr)) {
/* Thumb-2 32-bit */
- u16 tinst2 = 0;
- fault = probe_kernel_address(ptr + 1, tinst2);
- tinst2 = __mem_to_opcode_thumb16(tinst2);
+ u16 tinst2;
+ fault = alignment_get_thumb(regs, ptr + 1, &tinst2);
instr = __opcode_thumb32_compose(tinstr, tinst2);
thumb2_32b = 1;
} else {
@@ -803,8 +832,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
}
}
} else {
- fault = probe_kernel_address((void *)instrptr, instr);
- instr = __mem_to_opcode_arm(instr);
+ fault = alignment_get_arm(regs, (void *)instrptr, &instr);
}
if (fault) {
--
2.20.1
next prev parent reply other threads:[~2019-10-30 15:58 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-30 15:57 [PATCH AUTOSEL 4.4 01/13] regulator: ti-abb: Fix timeout in ti_abb_wait_txdone/ti_abb_clear_all_txdone Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 02/13] regulator: pfuze100-regulator: Variable "val" in pfuze100_regulator_probe() could be uninitialized Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 03/13] ASoc: rockchip: i2s: Fix RPM imbalance Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 04/13] ARM: dts: logicpd-torpedo-som: Remove twl_keypad Sasha Levin
2019-10-30 15:57 ` Sasha Levin [this message]
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 06/13] scsi: sni_53c710: fix compilation error Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 07/13] scsi: fix kconfig dependency warning related to 53C700_LE_ON_BE Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 08/13] USB: legousbtower: fix a signedness bug in tower_probe() Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 09/13] perf kmem: Fix memory leak in compact_gfp_flags() Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 10/13] scsi: target: core: Do not overwrite CDB byte 1 Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 11/13] of: unittest: fix memory leak in unittest_data_add Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 12/13] MIPS: bmips: mark exception vectors as char arrays Sasha Levin
2019-10-30 15:57 ` [PATCH AUTOSEL 4.4 13/13] cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs Sasha Levin
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