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Merge branch 'for-next/kprobes' into for-next/core

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* for-next/kprobes:
  arm64: kprobes: Return DBG_HOOK_ERROR if kprobes can not handle a BRK
  arm64: kprobes: Let arch do_page_fault() fix up page fault in user handler
  arm64: Prohibit instrumentation on arch_stack_walk()
This commit is contained in:
Will Deacon 2022-12-06 11:20:21 +00:00
commit 37f5d61a96
2 changed files with 42 additions and 56 deletions
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88
arch/arm64/kernel/probes/kprobes.c
View file

@ -294,19 +294,12 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr)
}
break;
case KPROBE_HIT_ACTIVE:
case KPROBE_HIT_SSDONE:
/*
* In case the user-specified fault handler returned
* zero, try to fix up.
*/
if (fixup_exception(regs))
return 1;
}
return 0;
}
static void __kprobes kprobe_handler(struct pt_regs *regs)
static int __kprobes
kprobe_breakpoint_handler(struct pt_regs *regs, unsigned long esr)
{
struct kprobe *p, *cur_kprobe;
struct kprobe_ctlblk *kcb;
@ -316,39 +309,44 @@ static void __kprobes kprobe_handler(struct pt_regs *regs)
cur_kprobe = kprobe_running();
p = get_kprobe((kprobe_opcode_t *) addr);
if (p) {
if (cur_kprobe) {
if (reenter_kprobe(p, regs, kcb))
return;
} else {
/* Probe hit */
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
/*
* If we have no pre-handler or it returned 0, we
* continue with normal processing. If we have a
* pre-handler and it returned non-zero, it will
* modify the execution path and no need to single
* stepping. Let's just reset current kprobe and exit.
*/
if (!p->pre_handler || !p->pre_handler(p, regs)) {
setup_singlestep(p, regs, kcb, 0);
} else
reset_current_kprobe();
}
if (WARN_ON_ONCE(!p)) {
/*
* Something went wrong. This BRK used an immediate reserved
* for kprobes, but we couldn't find any corresponding probe.
*/
return DBG_HOOK_ERROR;
}
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
* either a probepoint or a debugger breakpoint
* at this address. In either case, no further
* handling of this interrupt is appropriate.
* Return back to original instruction, and continue.
*/
if (cur_kprobe) {
/* Hit a kprobe inside another kprobe */
if (!reenter_kprobe(p, regs, kcb))
return DBG_HOOK_ERROR;
} else {
/* Probe hit */
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
/*
* If we have no pre-handler or it returned 0, we
* continue with normal processing. If we have a
* pre-handler and it returned non-zero, it will
* modify the execution path and not need to single-step
* Let's just reset current kprobe and exit.
*/
if (!p->pre_handler || !p->pre_handler(p, regs))
setup_singlestep(p, regs, kcb, 0);
else
reset_current_kprobe();
}
return DBG_HOOK_HANDLED;
}
static struct break_hook kprobes_break_hook = {
.imm = KPROBES_BRK_IMM,
.fn = kprobe_breakpoint_handler,
};
static int __kprobes
kprobe_breakpoint_ss_handler(struct pt_regs *regs, unsigned long esr)
{
@ -373,18 +371,6 @@ static struct break_hook kprobes_break_ss_hook = {
.fn = kprobe_breakpoint_ss_handler,
};
static int __kprobes
kprobe_breakpoint_handler(struct pt_regs *regs, unsigned long esr)
{
kprobe_handler(regs);
return DBG_HOOK_HANDLED;
}
static struct break_hook kprobes_break_hook = {
.imm = KPROBES_BRK_IMM,
.fn = kprobe_breakpoint_handler,
};
/*
* Provide a blacklist of symbols identifying ranges which cannot be kprobed.
* This blacklist is exposed to userspace via debugfs (kprobes/blacklist).

10
arch/arm64/kernel/stacktrace.c
View file

@ -23,8 +23,8 @@
*
* The regs must be on a stack currently owned by the calling task.
*/
static inline void unwind_init_from_regs(struct unwind_state *state,
struct pt_regs *regs)
static __always_inline void unwind_init_from_regs(struct unwind_state *state,
struct pt_regs *regs)
{
unwind_init_common(state, current);
@ -58,8 +58,8 @@ static __always_inline void unwind_init_from_caller(struct unwind_state *state)
* duration of the unwind, or the unwind will be bogus. It is never valid to
* call this for the current task.
*/
static inline void unwind_init_from_task(struct unwind_state *state,
struct task_struct *task)
static __always_inline void unwind_init_from_task(struct unwind_state *state,
struct task_struct *task)
{
unwind_init_common(state, task);
@ -186,7 +186,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
: stackinfo_get_unknown(); \
})
noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,
void *cookie, struct task_struct *task,
struct pt_regs *regs)
{