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Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm

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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
This commit is contained in:
Linus Torvalds 2017-11-09 17:41:39 -08:00
commit e7a7912a91
1 changed files with 18 additions and 10 deletions
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28
arch/arm/kernel/traps.c
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@ -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