Commit 6bf755db authored Aug 01, 2014 by Omar Sandoval Committed by Russell King Aug 02, 2014

ARM: 8124/1: don't enter kgdb when userspace executes a kgdb break instruction



The kgdb breakpoint hooks (kgdb_brk_fn and kgdb_compiled_brk_fn)
should only be entered when a kgdb break instruction is executed
from the kernel. Otherwise, if kgdb is enabled, a userspace program
can cause the kernel to drop into the debugger by executing either
KGDB_BREAKINST or KGDB_COMPILED_BREAK.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent c5cc87fa

arch/arm/kernel/kgdb.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -160,12 +160,16 @@ static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
		static struct undef_hook kgdb_brkpt_hook = {
		.instr_mask = 0xffffffff,
		.instr_val = KGDB_BREAKINST,
		.cpsr_mask = MODE_MASK,
		.cpsr_val = SVC_MODE,
		.fn = kgdb_brk_fn
		};

		static struct undef_hook kgdb_compiled_brkpt_hook = {
		.instr_mask = 0xffffffff,
		.instr_val = KGDB_COMPILED_BREAK,
		.cpsr_mask = MODE_MASK,
		.cpsr_val = SVC_MODE,
		.fn = kgdb_compiled_brk_fn
		};

Admin message