| Message ID | 1651753148-1464-3-git-send-email-yangtiezhu@loongson.cn |
|---|---|
| State | New |
| Headers | show |
| Series | Modify some code about kprobe | expand |
On Thu, 5 May 2022 20:19:08 +0800 Tiezhu Yang <yangtiezhu@loongson.cn> wrote: > If define CONFIG_KPROBES, __kprobes annotation forces the whole function > into the ".kprobes.text" section, NOKPROBE_SYMBOL() just stores the given > function address in the "_kprobe_blacklist" section which is introduced > to maintain kprobes blacklist. > > Modify the related code to use NOKPROBE_SYMBOL() to protect functions from > kprobes instead of __kprobes annotation under arch/mips. So you added some non '__kprobes' annotated functions to NOKPROBE_SYMBOL() in this patch. Those caused the kernel panic, right? If so, please add such comment on this description too. Or, split this into 2 patches, one fixes the kernel panic by adding those functions to NOKPROBE_SYMBOL() and the other is replacing __kprobes with NOKPROBE_SYMBOL(). Also, could you also find the commit which introduces the kernel panic? It is worth to backport such fix to stable trees. Thank you, > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > --- > arch/mips/kernel/kprobes.c | 45 ++++++++++++++++++++++++++++++++------------- > arch/mips/mm/fault.c | 6 ++++-- > 2 files changed, 36 insertions(+), 15 deletions(-) > > diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c > index 6c7f3b1..21f9cec 100644 > --- a/arch/mips/kernel/kprobes.c > +++ b/arch/mips/kernel/kprobes.c > @@ -44,10 +44,11 @@ static const union mips_instruction breakpoint2_insn = { > DEFINE_PER_CPU(struct kprobe *, current_kprobe); > DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); > > -static int __kprobes insn_has_delayslot(union mips_instruction insn) > +static int insn_has_delayslot(union mips_instruction insn) > { > return __insn_has_delay_slot(insn); > } > +NOKPROBE_SYMBOL(insn_has_delayslot); > > /* > * insn_has_ll_or_sc function checks whether instruction is ll or sc > @@ -56,7 +57,7 @@ static int __kprobes insn_has_delayslot(union mips_instruction insn) > * instructions; cannot do much about breakpoint in the middle of > * ll/sc pair; it is upto user to avoid those places > */ > -static int __kprobes insn_has_ll_or_sc(union mips_instruction insn) > +static int insn_has_ll_or_sc(union mips_instruction insn) > { > int ret = 0; > > @@ -72,8 +73,9 @@ static int __kprobes insn_has_ll_or_sc(union mips_instruction insn) > } > return ret; > } > +NOKPROBE_SYMBOL(insn_has_ll_or_sc); > > -int __kprobes arch_prepare_kprobe(struct kprobe *p) > +int arch_prepare_kprobe(struct kprobe *p) > { > union mips_instruction insn; > union mips_instruction prev_insn; > @@ -132,26 +134,30 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) > out: > return ret; > } > +NOKPROBE_SYMBOL(arch_prepare_kprobe); > > -void __kprobes arch_arm_kprobe(struct kprobe *p) > +void arch_arm_kprobe(struct kprobe *p) > { > *p->addr = breakpoint_insn; > flush_insn_slot(p); > } > +NOKPROBE_SYMBOL(arch_arm_kprobe); > > -void __kprobes arch_disarm_kprobe(struct kprobe *p) > +void arch_disarm_kprobe(struct kprobe *p) > { > *p->addr = p->opcode; > flush_insn_slot(p); > } > +NOKPROBE_SYMBOL(arch_disarm_kprobe); > > -void __kprobes arch_remove_kprobe(struct kprobe *p) > +void arch_remove_kprobe(struct kprobe *p) > { > if (p->ainsn.insn) { > free_insn_slot(p->ainsn.insn, 0); > p->ainsn.insn = NULL; > } > } > +NOKPROBE_SYMBOL(arch_remove_kprobe); > > static void save_previous_kprobe(struct kprobe_ctlblk *kcb) > { > @@ -161,6 +167,7 @@ static void save_previous_kprobe(struct kprobe_ctlblk *kcb) > kcb->prev_kprobe.saved_SR = kcb->kprobe_saved_SR; > kcb->prev_kprobe.saved_epc = kcb->kprobe_saved_epc; > } > +NOKPROBE_SYMBOL(save_previous_kprobe); > > static void restore_previous_kprobe(struct kprobe_ctlblk *kcb) > { > @@ -170,6 +177,7 @@ static void restore_previous_kprobe(struct kprobe_ctlblk *kcb) > kcb->kprobe_saved_SR = kcb->prev_kprobe.saved_SR; > kcb->kprobe_saved_epc = kcb->prev_kprobe.saved_epc; > } > +NOKPROBE_SYMBOL(restore_previous_kprobe); > > static void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, > struct kprobe_ctlblk *kcb) > @@ -178,6 +186,7 @@ static void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, > kcb->kprobe_saved_SR = kcb->kprobe_old_SR = (regs->cp0_status & ST0_IE); > kcb->kprobe_saved_epc = regs->cp0_epc; > } > +NOKPROBE_SYMBOL(set_current_kprobe); > > /** > * evaluate_branch_instrucion - > @@ -225,6 +234,7 @@ static int evaluate_branch_instruction(struct kprobe *p, struct pt_regs *regs, > return -EFAULT; > > } > +NOKPROBE_SYMBOL(evaluate_branch_instruction); > > static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs, > struct kprobe_ctlblk *kcb) > @@ -244,6 +254,7 @@ static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs, > } > regs->cp0_epc = (unsigned long)&p->ainsn.insn[0]; > } > +NOKPROBE_SYMBOL(prepare_singlestep); > > /* > * Called after single-stepping. p->addr is the address of the > @@ -257,7 +268,7 @@ static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs, > * breakpoint trap. In case of branch instructions, the target > * epc to be restored. > */ > -static void __kprobes resume_execution(struct kprobe *p, > +static void resume_execution(struct kprobe *p, > struct pt_regs *regs, > struct kprobe_ctlblk *kcb) > { > @@ -268,8 +279,9 @@ static void __kprobes resume_execution(struct kprobe *p, > regs->cp0_epc = orig_epc + 4; > } > } > +NOKPROBE_SYMBOL(resume_execution); > > -static int __kprobes kprobe_handler(struct pt_regs *regs) > +static int kprobe_handler(struct pt_regs *regs) > { > struct kprobe *p; > int ret = 0; > @@ -367,8 +379,9 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) > return ret; > > } > +NOKPROBE_SYMBOL(kprobe_handler); > > -static inline int post_kprobe_handler(struct pt_regs *regs) > +static int post_kprobe_handler(struct pt_regs *regs) > { > struct kprobe *cur = kprobe_running(); > struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); > @@ -396,6 +409,7 @@ static inline int post_kprobe_handler(struct pt_regs *regs) > > return 1; > } > +NOKPROBE_SYMBOL(post_kprobe_handler); > > int kprobe_fault_handler(struct pt_regs *regs, int trapnr) > { > @@ -411,11 +425,12 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) > } > return 0; > } > +NOKPROBE_SYMBOL(kprobe_fault_handler); > > /* > * Wrapper routine for handling exceptions. > */ > -int __kprobes kprobe_exceptions_notify(struct notifier_block *self, > +int kprobe_exceptions_notify(struct notifier_block *self, > unsigned long val, void *data) > { > > @@ -446,6 +461,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, > } > return ret; > } > +NOKPROBE_SYMBOL(kprobe_exceptions_notify); > > /* > * Function return probe trampoline: > @@ -469,7 +485,7 @@ static void __used kretprobe_trampoline_holder(void) > > void __kretprobe_trampoline(void); > > -void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, > +void arch_prepare_kretprobe(struct kretprobe_instance *ri, > struct pt_regs *regs) > { > ri->ret_addr = (kprobe_opcode_t *) regs->regs[31]; > @@ -478,11 +494,12 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, > /* Replace the return addr with trampoline addr */ > regs->regs[31] = (unsigned long)__kretprobe_trampoline; > } > +NOKPROBE_SYMBOL(arch_prepare_kretprobe); > > /* > * Called when the probe at kretprobe trampoline is hit > */ > -static int __kprobes trampoline_probe_handler(struct kprobe *p, > +static int trampoline_probe_handler(struct kprobe *p, > struct pt_regs *regs) > { > instruction_pointer(regs) = __kretprobe_trampoline_handler(regs, NULL); > @@ -493,14 +510,16 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, > */ > return 1; > } > +NOKPROBE_SYMBOL(trampoline_probe_handler); > > -int __kprobes arch_trampoline_kprobe(struct kprobe *p) > +int arch_trampoline_kprobe(struct kprobe *p) > { > if (p->addr == (kprobe_opcode_t *)__kretprobe_trampoline) > return 1; > > return 0; > } > +NOKPROBE_SYMBOL(arch_trampoline_kprobe); > > static struct kprobe trampoline_p = { > .addr = (kprobe_opcode_t *)__kretprobe_trampoline, > diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c > index 44f9810..b08bc55 100644 > --- a/arch/mips/mm/fault.c > +++ b/arch/mips/mm/fault.c > @@ -35,7 +35,7 @@ int show_unhandled_signals = 1; > * and the problem, and then passes it off to one of the appropriate > * routines. > */ > -static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, > +static void __do_page_fault(struct pt_regs *regs, unsigned long write, > unsigned long address) > { > struct vm_area_struct * vma = NULL; > @@ -322,8 +322,9 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, > } > #endif > } > +NOKPROBE_SYMBOL(__do_page_fault); > > -asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, > +asmlinkage void do_page_fault(struct pt_regs *regs, > unsigned long write, unsigned long address) > { > enum ctx_state prev_state; > @@ -332,3 +333,4 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, > __do_page_fault(regs, write, address); > exception_exit(prev_state); > } > +NOKPROBE_SYMBOL(do_page_fault); > -- > 2.1.0 >
On 05/06/2022 09:45 AM, Masami Hiramatsu wrote: > On Thu, 5 May 2022 20:19:08 +0800 > Tiezhu Yang <yangtiezhu@loongson.cn> wrote: > >> If define CONFIG_KPROBES, __kprobes annotation forces the whole function >> into the ".kprobes.text" section, NOKPROBE_SYMBOL() just stores the given >> function address in the "_kprobe_blacklist" section which is introduced >> to maintain kprobes blacklist. >> >> Modify the related code to use NOKPROBE_SYMBOL() to protect functions from >> kprobes instead of __kprobes annotation under arch/mips. > > So you added some non '__kprobes' annotated functions to NOKPROBE_SYMBOL() > in this patch. Those caused the kernel panic, right? Oh, no, this patch is not related with the kernel panic, what it does is just to use NOKPROBE_SYMBOL() instead of __kprobes annotation, and also add some non '__kprobes' annotated functions in kprobes.c to NOKPROBE_SYMBOL() because they can not be probed too. > If so, please add such > comment on this description too. Or, split this into 2 patches, one fixes > the kernel panic by adding those functions to NOKPROBE_SYMBOL() and the > other is replacing __kprobes with NOKPROBE_SYMBOL(). > > Also, could you also find the commit which introduces the kernel panic? > It is worth to backport such fix to stable trees. I did some work to find some other functions lead to kernel panic, mark them as notrace function can avoid the problems, but I am not quite sure the root cause, so I do not submit the changes now. Thanks, Tiezhu
diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c index 6c7f3b1..21f9cec 100644 --- a/arch/mips/kernel/kprobes.c +++ b/arch/mips/kernel/kprobes.c @@ -44,10 +44,11 @@ static const union mips_instruction breakpoint2_insn = { DEFINE_PER_CPU(struct kprobe *, current_kprobe); DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); -static int __kprobes insn_has_delayslot(union mips_instruction insn) +static int insn_has_delayslot(union mips_instruction insn) { return __insn_has_delay_slot(insn); } +NOKPROBE_SYMBOL(insn_has_delayslot); /* * insn_has_ll_or_sc function checks whether instruction is ll or sc @@ -56,7 +57,7 @@ static int __kprobes insn_has_delayslot(union mips_instruction insn) * instructions; cannot do much about breakpoint in the middle of * ll/sc pair; it is upto user to avoid those places */ -static int __kprobes insn_has_ll_or_sc(union mips_instruction insn) +static int insn_has_ll_or_sc(union mips_instruction insn) { int ret = 0; @@ -72,8 +73,9 @@ static int __kprobes insn_has_ll_or_sc(union mips_instruction insn) } return ret; } +NOKPROBE_SYMBOL(insn_has_ll_or_sc); -int __kprobes arch_prepare_kprobe(struct kprobe *p) +int arch_prepare_kprobe(struct kprobe *p) { union mips_instruction insn; union mips_instruction prev_insn; @@ -132,26 +134,30 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) out: return ret; } +NOKPROBE_SYMBOL(arch_prepare_kprobe); -void __kprobes arch_arm_kprobe(struct kprobe *p) +void arch_arm_kprobe(struct kprobe *p) { *p->addr = breakpoint_insn; flush_insn_slot(p); } +NOKPROBE_SYMBOL(arch_arm_kprobe); -void __kprobes arch_disarm_kprobe(struct kprobe *p) +void arch_disarm_kprobe(struct kprobe *p) { *p->addr = p->opcode; flush_insn_slot(p); } +NOKPROBE_SYMBOL(arch_disarm_kprobe); -void __kprobes arch_remove_kprobe(struct kprobe *p) +void arch_remove_kprobe(struct kprobe *p) { if (p->ainsn.insn) { free_insn_slot(p->ainsn.insn, 0); p->ainsn.insn = NULL; } } +NOKPROBE_SYMBOL(arch_remove_kprobe); static void save_previous_kprobe(struct kprobe_ctlblk *kcb) { @@ -161,6 +167,7 @@ static void save_previous_kprobe(struct kprobe_ctlblk *kcb) kcb->prev_kprobe.saved_SR = kcb->kprobe_saved_SR; kcb->prev_kprobe.saved_epc = kcb->kprobe_saved_epc; } +NOKPROBE_SYMBOL(save_previous_kprobe); static void restore_previous_kprobe(struct kprobe_ctlblk *kcb) { @@ -170,6 +177,7 @@ static void restore_previous_kprobe(struct kprobe_ctlblk *kcb) kcb->kprobe_saved_SR = kcb->prev_kprobe.saved_SR; kcb->kprobe_saved_epc = kcb->prev_kprobe.saved_epc; } +NOKPROBE_SYMBOL(restore_previous_kprobe); static void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) @@ -178,6 +186,7 @@ static void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, kcb->kprobe_saved_SR = kcb->kprobe_old_SR = (regs->cp0_status & ST0_IE); kcb->kprobe_saved_epc = regs->cp0_epc; } +NOKPROBE_SYMBOL(set_current_kprobe); /** * evaluate_branch_instrucion - @@ -225,6 +234,7 @@ static int evaluate_branch_instruction(struct kprobe *p, struct pt_regs *regs, return -EFAULT; } +NOKPROBE_SYMBOL(evaluate_branch_instruction); static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) @@ -244,6 +254,7 @@ static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs, } regs->cp0_epc = (unsigned long)&p->ainsn.insn[0]; } +NOKPROBE_SYMBOL(prepare_singlestep); /* * Called after single-stepping. p->addr is the address of the @@ -257,7 +268,7 @@ static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs, * breakpoint trap. In case of branch instructions, the target * epc to be restored. */ -static void __kprobes resume_execution(struct kprobe *p, +static void resume_execution(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { @@ -268,8 +279,9 @@ static void __kprobes resume_execution(struct kprobe *p, regs->cp0_epc = orig_epc + 4; } } +NOKPROBE_SYMBOL(resume_execution); -static int __kprobes kprobe_handler(struct pt_regs *regs) +static int kprobe_handler(struct pt_regs *regs) { struct kprobe *p; int ret = 0; @@ -367,8 +379,9 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) return ret; } +NOKPROBE_SYMBOL(kprobe_handler); -static inline int post_kprobe_handler(struct pt_regs *regs) +static int post_kprobe_handler(struct pt_regs *regs) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -396,6 +409,7 @@ static inline int post_kprobe_handler(struct pt_regs *regs) return 1; } +NOKPROBE_SYMBOL(post_kprobe_handler); int kprobe_fault_handler(struct pt_regs *regs, int trapnr) { @@ -411,11 +425,12 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) } return 0; } +NOKPROBE_SYMBOL(kprobe_fault_handler); /* * Wrapper routine for handling exceptions. */ -int __kprobes kprobe_exceptions_notify(struct notifier_block *self, +int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data) { @@ -446,6 +461,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, } return ret; } +NOKPROBE_SYMBOL(kprobe_exceptions_notify); /* * Function return probe trampoline: @@ -469,7 +485,7 @@ static void __used kretprobe_trampoline_holder(void) void __kretprobe_trampoline(void); -void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, +void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { ri->ret_addr = (kprobe_opcode_t *) regs->regs[31]; @@ -478,11 +494,12 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, /* Replace the return addr with trampoline addr */ regs->regs[31] = (unsigned long)__kretprobe_trampoline; } +NOKPROBE_SYMBOL(arch_prepare_kretprobe); /* * Called when the probe at kretprobe trampoline is hit */ -static int __kprobes trampoline_probe_handler(struct kprobe *p, +static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { instruction_pointer(regs) = __kretprobe_trampoline_handler(regs, NULL); @@ -493,14 +510,16 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, */ return 1; } +NOKPROBE_SYMBOL(trampoline_probe_handler); -int __kprobes arch_trampoline_kprobe(struct kprobe *p) +int arch_trampoline_kprobe(struct kprobe *p) { if (p->addr == (kprobe_opcode_t *)__kretprobe_trampoline) return 1; return 0; } +NOKPROBE_SYMBOL(arch_trampoline_kprobe); static struct kprobe trampoline_p = { .addr = (kprobe_opcode_t *)__kretprobe_trampoline, diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c index 44f9810..b08bc55 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -35,7 +35,7 @@ int show_unhandled_signals = 1; * and the problem, and then passes it off to one of the appropriate * routines. */ -static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, +static void __do_page_fault(struct pt_regs *regs, unsigned long write, unsigned long address) { struct vm_area_struct * vma = NULL; @@ -322,8 +322,9 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, } #endif } +NOKPROBE_SYMBOL(__do_page_fault); -asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, +asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write, unsigned long address) { enum ctx_state prev_state; @@ -332,3 +333,4 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, __do_page_fault(regs, write, address); exception_exit(prev_state); } +NOKPROBE_SYMBOL(do_page_fault);
If define CONFIG_KPROBES, __kprobes annotation forces the whole function into the ".kprobes.text" section, NOKPROBE_SYMBOL() just stores the given function address in the "_kprobe_blacklist" section which is introduced to maintain kprobes blacklist. Modify the related code to use NOKPROBE_SYMBOL() to protect functions from kprobes instead of __kprobes annotation under arch/mips. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- arch/mips/kernel/kprobes.c | 45 ++++++++++++++++++++++++++++++++------------- arch/mips/mm/fault.c | 6 ++++-- 2 files changed, 36 insertions(+), 15 deletions(-)