From: Prasanna S Panchamukhi This patch modifies the return value of kprobes exceptions notify handler. The kprobes exception notifier returns NOTIFY_STOP on handling notification. This patch helps other debuggers to co-exists with the Kprobes. Other debuggers registered for exceptions notification must return NOTIFY_STOP on handling the notification. Signed-Off-By : Prasanna S Panchamukhi Signed-off-by: Andrew Morton --- /dev/null | 0 25-akpm/arch/i386/kernel/kprobes.c | 10 +++++----- 25-akpm/arch/i386/kernel/traps.c | 12 ++++++------ 25-akpm/arch/i386/mm/fault.c | 2 +- 25-akpm/arch/sparc64/kernel/kprobes.c | 12 ++++++------ 25-akpm/arch/sparc64/kernel/traps.c | 28 ++++++++++++++-------------- 25-akpm/arch/sparc64/mm/fault.c | 4 ++-- 25-akpm/arch/x86_64/kernel/nmi.c | 3 ++- 25-akpm/arch/x86_64/kernel/traps.c | 16 ++++++++++------ 25-akpm/include/linux/notifier.h | 4 ++++ 25-akpm/kernel/kprobes.c | 3 +++ 11 files changed, 53 insertions(+), 41 deletions(-) diff -puN arch/i386/kernel/kprobes.c~kprobes-exception-notifier-fix arch/i386/kernel/kprobes.c --- 25/arch/i386/kernel/kprobes.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/arch/i386/kernel/kprobes.c Thu Sep 30 14:58:50 2004 @@ -267,26 +267,26 @@ int kprobe_exceptions_notify(struct noti switch (val) { case DIE_INT3: if (kprobe_handler(args->regs)) - return NOTIFY_OK; + return NOTIFY_STOP; break; case DIE_DEBUG: if (post_kprobe_handler(args->regs)) - return NOTIFY_OK; + return NOTIFY_STOP; break; case DIE_GPF: if (kprobe_running() && kprobe_fault_handler(args->regs, args->trapnr)) - return NOTIFY_OK; + return NOTIFY_STOP; break; case DIE_PAGE_FAULT: if (kprobe_running() && kprobe_fault_handler(args->regs, args->trapnr)) - return NOTIFY_OK; + return NOTIFY_STOP; break; default: break; } - return NOTIFY_BAD; + return NOTIFY_DONE; } int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) diff -puN arch/i386/kernel/traps.c~kprobes-exception-notifier-fix arch/i386/kernel/traps.c --- 25/arch/i386/kernel/traps.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/arch/i386/kernel/traps.c Thu Sep 30 14:58:50 2004 @@ -459,7 +459,7 @@ asmlinkage void do_##name(struct pt_regs info.si_code = sicode; \ info.si_addr = (void __user *)siaddr; \ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ - == NOTIFY_OK) \ + == NOTIFY_STOP) \ return; \ do_trap(trapnr, signr, str, 1, regs, error_code, &info); \ } @@ -528,7 +528,7 @@ gp_in_vm86: gp_in_kernel: if (!fixup_exception(regs)) { if (notify_die(DIE_GPF, "general protection fault", regs, - error_code, 13, SIGSEGV) == NOTIFY_OK); + error_code, 13, SIGSEGV) == NOTIFY_STOP); return; die("general protection fault", regs, error_code); } @@ -602,7 +602,7 @@ static void default_do_nmi(struct pt_reg if (!(reason & 0xc0)) { if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 0, SIGINT) - == NOTIFY_BAD) + == NOTIFY_STOP) return; #ifdef CONFIG_X86_LOCAL_APIC /* @@ -617,7 +617,7 @@ static void default_do_nmi(struct pt_reg unknown_nmi_error(reason, regs); return; } - if (notify_die(DIE_NMI, "nmi", regs, reason, 0, SIGINT) == NOTIFY_BAD) + if (notify_die(DIE_NMI, "nmi", regs, reason, 0, SIGINT) == NOTIFY_STOP) return; if (reason & 0x80) mem_parity_error(reason, regs); @@ -666,7 +666,7 @@ void unset_nmi_callback(void) asmlinkage int do_int3(struct pt_regs *regs, long error_code) { if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) - == NOTIFY_OK) + == NOTIFY_STOP) return 1; /* This is an interrupt gate, because kprobes wants interrupts disabled. Normal trap handlers don't. */ @@ -707,7 +707,7 @@ asmlinkage void do_debug(struct pt_regs __asm__ __volatile__("movl %%db6,%0" : "=r" (condition)); if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code, - SIGTRAP) == NOTIFY_OK) + SIGTRAP) == NOTIFY_STOP) return; /* It's safe to allow irq's after DR6 has been saved */ if (regs->eflags & X86_EFLAGS_IF) diff -puN arch/i386/mm/fault.c~kprobes-exception-notifier-fix arch/i386/mm/fault.c --- 25/arch/i386/mm/fault.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/arch/i386/mm/fault.c Thu Sep 30 14:58:50 2004 @@ -227,7 +227,7 @@ asmlinkage void do_page_fault(struct pt_ __asm__("movl %%cr2,%0":"=r" (address)); if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14, - SIGSEGV) == NOTIFY_OK) + SIGSEGV) == NOTIFY_STOP) return; /* It's safe to allow irq's after cr2 has been saved */ if (regs->eflags & (X86_EFLAGS_IF|VM_MASK)) diff -puN arch/sparc64/kernel/kprobes.c~kprobes-exception-notifier-fix arch/sparc64/kernel/kprobes.c --- 25/arch/sparc64/kernel/kprobes.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/arch/sparc64/kernel/kprobes.c Thu Sep 30 14:58:50 2004 @@ -179,26 +179,26 @@ int kprobe_exceptions_notify(struct noti switch (val) { case DIE_DEBUG: if (kprobe_handler(args->regs)) - return NOTIFY_OK; + return NOTIFY_STOP; break; case DIE_DEBUG_2: if (post_kprobe_handler(args->regs)) - return NOTIFY_OK; + return NOTIFY_STOP; break; case DIE_GPF: if (kprobe_running() && kprobe_fault_handler(args->regs, args->trapnr)) - return NOTIFY_OK; + return NOTIFY_STOP; break; case DIE_PAGE_FAULT: if (kprobe_running() && kprobe_fault_handler(args->regs, args->trapnr)) - return NOTIFY_OK; + return NOTIFY_STOP; break; default: break; } - return NOTIFY_BAD; + return NOTIFY_DONE; } asmlinkage void kprobe_trap(unsigned long trap_level, struct pt_regs *regs) @@ -216,7 +216,7 @@ asmlinkage void kprobe_trap(unsigned lon */ if (notify_die((trap_level == 0x170) ? DIE_DEBUG : DIE_DEBUG_2, (trap_level == 0x170) ? "debug" : "debug_2", - regs, 0, trap_level, SIGTRAP) != NOTIFY_OK) + regs, 0, trap_level, SIGTRAP) != NOTIFY_STOP) bad_trap(regs, trap_level); } diff -puN arch/sparc64/kernel/traps.c~kprobes-exception-notifier-fix arch/sparc64/kernel/traps.c --- 25/arch/sparc64/kernel/traps.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/arch/sparc64/kernel/traps.c Thu Sep 30 14:58:50 2004 @@ -96,7 +96,7 @@ void bad_trap(struct pt_regs *regs, long siginfo_t info; if (notify_die(DIE_TRAP, "bad trap", regs, - 0, lvl, SIGTRAP) == NOTIFY_OK) + 0, lvl, SIGTRAP) == NOTIFY_STOP) return; if (lvl < 0x100) { @@ -126,7 +126,7 @@ void bad_trap_tl1(struct pt_regs *regs, char buffer[32]; if (notify_die(DIE_TRAP_TL1, "bad trap tl1", regs, - 0, lvl, SIGTRAP) == NOTIFY_OK) + 0, lvl, SIGTRAP) == NOTIFY_STOP) return; dump_tl1_traplog((struct tl1_traplog *)(regs + 1)); @@ -149,7 +149,7 @@ void instruction_access_exception(struct siginfo_t info; if (notify_die(DIE_TRAP, "instruction access exception", regs, - 0, 0x8, SIGTRAP) == NOTIFY_OK) + 0, 0x8, SIGTRAP) == NOTIFY_STOP) return; if (regs->tstate & TSTATE_PRIV) { @@ -173,7 +173,7 @@ void instruction_access_exception_tl1(st unsigned long sfsr, unsigned long sfar) { if (notify_die(DIE_TRAP_TL1, "instruction access exception tl1", regs, - 0, 0x8, SIGTRAP) == NOTIFY_OK) + 0, 0x8, SIGTRAP) == NOTIFY_STOP) return; dump_tl1_traplog((struct tl1_traplog *)(regs + 1)); @@ -186,7 +186,7 @@ void data_access_exception(struct pt_reg siginfo_t info; if (notify_die(DIE_TRAP, "data access exception", regs, - 0, 0x30, SIGTRAP) == NOTIFY_OK) + 0, 0x30, SIGTRAP) == NOTIFY_STOP) return; if (regs->tstate & TSTATE_PRIV) { @@ -260,7 +260,7 @@ void do_iae(struct pt_regs *regs) spitfire_clean_and_reenable_l1_caches(); if (notify_die(DIE_TRAP, "instruction access exception", regs, - 0, 0x8, SIGTRAP) == NOTIFY_OK) + 0, 0x8, SIGTRAP) == NOTIFY_STOP) return; info.si_signo = SIGBUS; @@ -292,7 +292,7 @@ void do_dae(struct pt_regs *regs) spitfire_clean_and_reenable_l1_caches(); if (notify_die(DIE_TRAP, "data access exception", regs, - 0, 0x30, SIGTRAP) == NOTIFY_OK) + 0, 0x30, SIGTRAP) == NOTIFY_STOP) return; info.si_signo = SIGBUS; @@ -1695,7 +1695,7 @@ void do_fpe_common(struct pt_regs *regs) void do_fpieee(struct pt_regs *regs) { if (notify_die(DIE_TRAP, "fpu exception ieee", regs, - 0, 0x24, SIGFPE) == NOTIFY_OK) + 0, 0x24, SIGFPE) == NOTIFY_STOP) return; do_fpe_common(regs); @@ -1709,7 +1709,7 @@ void do_fpother(struct pt_regs *regs) int ret = 0; if (notify_die(DIE_TRAP, "fpu exception other", regs, - 0, 0x25, SIGFPE) == NOTIFY_OK) + 0, 0x25, SIGFPE) == NOTIFY_STOP) return; switch ((current_thread_info()->xfsr[0] & 0x1c000)) { @@ -1728,7 +1728,7 @@ void do_tof(struct pt_regs *regs) siginfo_t info; if (notify_die(DIE_TRAP, "tagged arithmetic overflow", regs, - 0, 0x26, SIGEMT) == NOTIFY_OK) + 0, 0x26, SIGEMT) == NOTIFY_STOP) return; if (regs->tstate & TSTATE_PRIV) @@ -1750,7 +1750,7 @@ void do_div0(struct pt_regs *regs) siginfo_t info; if (notify_die(DIE_TRAP, "integer division by zero", regs, - 0, 0x28, SIGFPE) == NOTIFY_OK) + 0, 0x28, SIGFPE) == NOTIFY_STOP) return; if (regs->tstate & TSTATE_PRIV) @@ -1936,7 +1936,7 @@ void do_illegal_instruction(struct pt_re siginfo_t info; if (notify_die(DIE_TRAP, "illegal instruction", regs, - 0, 0x10, SIGILL) == NOTIFY_OK) + 0, 0x10, SIGILL) == NOTIFY_STOP) return; if (tstate & TSTATE_PRIV) @@ -1965,7 +1965,7 @@ void mem_address_unaligned(struct pt_reg siginfo_t info; if (notify_die(DIE_TRAP, "memory address unaligned", regs, - 0, 0x34, SIGSEGV) == NOTIFY_OK) + 0, 0x34, SIGSEGV) == NOTIFY_STOP) return; if (regs->tstate & TSTATE_PRIV) { @@ -1991,7 +1991,7 @@ void do_privop(struct pt_regs *regs) siginfo_t info; if (notify_die(DIE_TRAP, "privileged operation", regs, - 0, 0x11, SIGILL) == NOTIFY_OK) + 0, 0x11, SIGILL) == NOTIFY_STOP) return; if (test_thread_flag(TIF_32BIT)) { diff -puN arch/sparc64/mm/fault.c~kprobes-exception-notifier-fix arch/sparc64/mm/fault.c --- 25/arch/sparc64/mm/fault.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/arch/sparc64/mm/fault.c Thu Sep 30 14:58:50 2004 @@ -149,7 +149,7 @@ static void unhandled_fault(unsigned lon (tsk->mm ? (unsigned long) tsk->mm->pgd : (unsigned long) tsk->active_mm->pgd)); if (notify_die(DIE_GPF, "general protection fault", regs, - 0, 0, SIGSEGV) == NOTIFY_OK) + 0, 0, SIGSEGV) == NOTIFY_STOP) return; die_if_kernel("Oops", regs); } @@ -325,7 +325,7 @@ asmlinkage void do_sparc64_fault(struct fault_code = get_thread_fault_code(); if (notify_die(DIE_PAGE_FAULT, "page_fault", regs, - fault_code, 0, SIGSEGV) == NOTIFY_OK) + fault_code, 0, SIGSEGV) == NOTIFY_STOP) return; si_code = SEGV_MAPERR; diff -L arch/x86_64/kernel/kgdb_stub.c -puN /dev/null /dev/null diff -puN arch/x86_64/kernel/nmi.c~kprobes-exception-notifier-fix arch/x86_64/kernel/nmi.c --- 25/arch/x86_64/kernel/nmi.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/arch/x86_64/kernel/nmi.c Thu Sep 30 14:58:50 2004 @@ -390,7 +390,8 @@ void nmi_watchdog_tick (struct pt_regs * */ alert_counter[cpu]++; if (alert_counter[cpu] == 5*nmi_hz) { - if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_BAD) { + if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) + == NOTIFY_STOP) { alert_counter[cpu] = 0; return; } diff -puN arch/x86_64/kernel/traps.c~kprobes-exception-notifier-fix arch/x86_64/kernel/traps.c --- 25/arch/x86_64/kernel/traps.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/arch/x86_64/kernel/traps.c Thu Sep 30 14:58:50 2004 @@ -437,7 +437,8 @@ static void do_trap(int trapnr, int sign #define DO_ERROR(trapnr, signr, str, name) \ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ { \ - if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) == NOTIFY_BAD) \ + if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ + == NOTIFY_STOP) \ return; \ do_trap(trapnr, signr, str, regs, error_code, NULL); \ } @@ -450,7 +451,8 @@ asmlinkage void do_##name(struct pt_regs info.si_errno = 0; \ info.si_code = sicode; \ info.si_addr = (void __user *)siaddr; \ - if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) == NOTIFY_BAD) \ + if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ + == NOTIFY_STOP) \ return; \ do_trap(trapnr, signr, str, regs, error_code, &info); \ } @@ -471,7 +473,8 @@ DO_ERROR(18, SIGSEGV, "reserved", reserv asmlinkage void *do_##name(struct pt_regs * regs, long error_code) \ { \ struct pt_regs *pr = ((struct pt_regs *)(current->thread.rsp0))-1; \ - if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) == NOTIFY_BAD) \ + if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ + == NOTIFY_STOP) \ return regs; \ if (regs->cs & 3) { \ memcpy(pr, regs, sizeof(struct pt_regs)); \ @@ -565,7 +568,8 @@ asmlinkage void default_do_nmi(struct pt unsigned char reason = inb(0x61); if (!(reason & 0xc0)) { - if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 0, SIGINT) == NOTIFY_BAD) + if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 0, SIGINT) + == NOTIFY_STOP) return; #ifdef CONFIG_X86_LOCAL_APIC /* @@ -580,7 +584,7 @@ asmlinkage void default_do_nmi(struct pt unknown_nmi_error(reason, regs); return; } - if (notify_die(DIE_NMI, "nmi", regs, reason, 0, SIGINT) == NOTIFY_BAD) + if (notify_die(DIE_NMI, "nmi", regs, reason, 0, SIGINT) == NOTIFY_STOP) return; if (reason & 0x80) mem_parity_error(reason, regs); @@ -676,7 +680,7 @@ clear_TF_reenable: clear_TF: /* RED-PEN could cause spurious errors */ if (notify_die(DIE_DEBUG, "debug2", regs, condition, 1, SIGTRAP) - != NOTIFY_BAD) + != NOTIFY_STOP) regs->eflags &= ~TF_MASK; return regs; } diff -puN include/linux/notifier.h~kprobes-exception-notifier-fix include/linux/notifier.h --- 25/include/linux/notifier.h~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/include/linux/notifier.h Thu Sep 30 14:58:50 2004 @@ -29,6 +29,10 @@ extern int notifier_call_chain(struct no #define NOTIFY_OK 0x0001 /* Suits me */ #define NOTIFY_STOP_MASK 0x8000 /* Don't call further */ #define NOTIFY_BAD (NOTIFY_STOP_MASK|0x0002) /* Bad/Veto action */ +/* + * Clean way to return from the notifier and stop further calls. + */ +#define NOTIFY_STOP (NOTIFY_OK|NOTIFY_STOP_MASK) /* * Declared notifiers so far. I can imagine quite a few more chains diff -puN kernel/kprobes.c~kprobes-exception-notifier-fix kernel/kprobes.c --- 25/kernel/kprobes.c~kprobes-exception-notifier-fix Thu Sep 30 14:58:50 2004 +++ 25-akpm/kernel/kprobes.c Thu Sep 30 14:58:50 2004 @@ -25,6 +25,8 @@ * hlists and exceptions notifier as suggested by Andi Kleen. * 2004-July Suparna Bhattacharya added jumper probes * interface to access function arguments. + * 2004-Sep Prasanna S Panchamukhi Changed Kprobes + * exceptions notifier to be first on the priority list. */ #include #include @@ -108,6 +110,7 @@ void unregister_kprobe(struct kprobe *p) static struct notifier_block kprobe_exceptions_nb = { .notifier_call = kprobe_exceptions_notify, + .priority = 0x7fffffff /* we need to notified first */ }; int register_jprobe(struct jprobe *jp) _