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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-09 17:41:39 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-09 17:41:39 -0800
commite7a7912a91cc1a274fab17f8a66b1e9dcfe00047 (patch)
treed6a7e32b9af7227e16265f3f280fe97b2b766af4 /arch/arm
parent3fefc31843cfe2b5f072efe11ed9ccaf6a7a5092 (diff)
parentb9dd05c7002ee0ca8b676428b2268c26399b5e31 (diff)
downloadlinux-e7a7912a91cc1a274fab17f8a66b1e9dcfe00047.tar.bz2
Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM fix from Russell King: "Last ARM fix for 4.14. This plugs a hole in dump_instr(), which, with certain conditions satisfied, can dump instructions from kernel space" * 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8720/1: ensure dump_instr() checks addr_limit
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/kernel/traps.c28
1 files changed, 18 insertions, 10 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 948c648fea00..0fcd82f01388 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -154,30 +154,26 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
set_fs(fs);
}
-static void dump_instr(const char *lvl, struct pt_regs *regs)
+static void __dump_instr(const char *lvl, struct pt_regs *regs)
{
unsigned long addr = instruction_pointer(regs);
const int thumb = thumb_mode(regs);
const int width = thumb ? 4 : 8;
- mm_segment_t fs;
char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
int i;
/*
- * We need to switch to kernel mode so that we can use __get_user
- * to safely read from kernel space. Note that we now dump the
- * code first, just in case the backtrace kills us.
+ * Note that we now dump the code first, just in case the backtrace
+ * kills us.
*/
- fs = get_fs();
- set_fs(KERNEL_DS);
for (i = -4; i < 1 + !!thumb; i++) {
unsigned int val, bad;
if (thumb)
- bad = __get_user(val, &((u16 *)addr)[i]);
+ bad = get_user(val, &((u16 *)addr)[i]);
else
- bad = __get_user(val, &((u32 *)addr)[i]);
+ bad = get_user(val, &((u32 *)addr)[i]);
if (!bad)
p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
@@ -188,8 +184,20 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
}
}
printk("%sCode: %s\n", lvl, str);
+}
- set_fs(fs);
+static void dump_instr(const char *lvl, struct pt_regs *regs)
+{
+ mm_segment_t fs;
+
+ if (!user_mode(regs)) {
+ fs = get_fs();
+ set_fs(KERNEL_DS);
+ __dump_instr(lvl, regs);
+ set_fs(fs);
+ } else {
+ __dump_instr(lvl, regs);
+ }
}
#ifdef CONFIG_ARM_UNWIND