diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2018-04-03 13:22:51 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2018-04-24 21:07:36 +0300 |
| commit | 9478f1927e6ef9ef5e1ad761af1c98aa8e40b7f5 (patch) | |
| tree | 585789158e71ac5acce4a4f7146b803a26813e8b /arch | |
| parent | ed231ae384fdfcb546b63b2fe7add65029e3a94c (diff) | |
| download | linux-9478f1927e6ef9ef5e1ad761af1c98aa8e40b7f5.tar.xz | |
arm64: only advance singlestep for user instruction traps
Our arm64_skip_faulting_instruction() helper advances the userspace
singlestep state machine, but this is also called by the kernel BRK
handler, as used for WARN*().
Thus, if we happen to hit a WARN*() while the user singlestep state
machine is in the active-no-pending state, we'll advance to the
active-pending state without having executed a user instruction, and
will take a step exception earlier than expected when we return to
userspace.
Let's fix this by only advancing the state machine when skipping a user
instruction.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/kernel/traps.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 1cb2749a72bf..8bbdc17e49df 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -277,7 +277,8 @@ void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size) * If we were single stepping, we want to get the step exception after * we return from the trap. */ - user_fastforward_single_step(current); + if (user_mode(regs)) + user_fastforward_single_step(current); } static LIST_HEAD(undef_hook); |