| Message ID | 20140718225049.GA11937@mew.guest.dropbox.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jul 18, 2014 at 03:51:31PM -0700, Omar Sandoval wrote: > Don't break into kgdb when userspace executes the kernel break instructions > (KGDB_BREAKINST and KGDB_COMPILED_BREAK). The kernel will oops in > kgdb_handle_exception. > > Signed-off-by: Omar Sandoval <osandov@osandov.com> > --- > The following program will immediately cause a kernel oops: > .globl _start > _start: > udf #65006 @ KGDB_BREAKINST > > arch/arm/kernel/kgdb.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c > index 778c2f7..a74b53c 100644 > --- a/arch/arm/kernel/kgdb.c > +++ b/arch/arm/kernel/kgdb.c > @@ -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 > }; > > -- > 2.0.1
diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c index 778c2f7..a74b53c 100644 --- a/arch/arm/kernel/kgdb.c +++ b/arch/arm/kernel/kgdb.c @@ -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 };
Don't break into kgdb when userspace executes the kernel break instructions (KGDB_BREAKINST and KGDB_COMPILED_BREAK). The kernel will oops in kgdb_handle_exception. Signed-off-by: Omar Sandoval <osandov@osandov.com> --- The following program will immediately cause a kernel oops: .globl _start _start: udf #65006 @ KGDB_BREAKINST arch/arm/kernel/kgdb.c | 4 ++++ 1 file changed, 4 insertions(+)