From: Oleg Nesterov [PATCH] signals: check ->group_stop_count after tracehook_get_signal() Move the call to do_signal_stop() down, after tracehook call. This makes ->group_stop_count condition visible to tracers before do_signal_stop() will participate in this group-stop. Currently the patch has no effect, tracehook_get_signal() always returns 0. Signed-off-by: Oleg Nesterov Signed-off-by: Roland McGrath --- arch/powerpc/include/asm/ptrace.h | 2 + arch/powerpc/kernel/traps.c | 9 ++++++ arch/s390/kernel/traps.c | 6 ++-- arch/x86/include/asm/ptrace.h | 2 + arch/x86/kernel/ptrace.c | 51 ++++++++++++++++++++---------------- include/linux/ptrace.h | 24 +++++++++++------ include/linux/sched.h | 1 + include/linux/tracehook.h | 15 ++++++++--- kernel/ptrace.c | 2 +- kernel/signal.c | 13 ++++----- 10 files changed, 79 insertions(+), 46 deletions(-) diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h index 8c34149..cbd759e 100644 --- a/arch/powerpc/include/asm/ptrace.h +++ b/arch/powerpc/include/asm/ptrace.h @@ -140,6 +140,8 @@ extern void user_enable_single_step(stru extern void user_enable_block_step(struct task_struct *); extern void user_disable_single_step(struct task_struct *); +#define ARCH_HAS_USER_SINGLE_STEP_INFO + #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 6f0ae1a..83b57ac 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -174,6 +174,15 @@ int die(const char *str, struct pt_regs return 0; } +void user_single_step_siginfo(struct task_struct *tsk, + struct pt_regs *regs, siginfo_t *info) +{ + memset(info, 0, sizeof(*info)); + info->si_signo = SIGTRAP; + info->si_code = TRAP_TRACE; + info->si_addr = (void __user *)regs->nip; +} + void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr) { siginfo_t info; diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c index c2e42cc..6e7ad63 100644 --- a/arch/s390/kernel/traps.c +++ b/arch/s390/kernel/traps.c @@ -18,7 +18,7 @@ #include #include #include -#include +#include #include #include #include @@ -382,7 +382,7 @@ void __kprobes do_single_step(struct pt_ SIGTRAP) == NOTIFY_STOP){ return; } - if ((current->ptrace & PT_PTRACED) != 0) + if (tracehook_consider_fatal_signal(current, SIGTRAP)) force_sig(SIGTRAP, current); } @@ -483,7 +483,7 @@ static void illegal_op(struct pt_regs * if (get_user(*((__u16 *) opcode), (__u16 __user *) location)) return; if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) { - if (current->ptrace & PT_PTRACED) + if (tracehook_consider_fatal_signal(current, SIGTRAP)) force_sig(SIGTRAP, current); else signal = SIGILL; diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 0f0d908..7a88a82 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -230,6 +230,8 @@ extern void user_enable_block_step(struc #define arch_has_block_step() (boot_cpu_data.x86 >= 6) #endif +#define ARCH_HAS_USER_SINGLE_STEP_INFO + struct user_desc; extern int do_get_thread_area(struct task_struct *p, int idx, struct user_desc __user *info); diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 7b058a2..ea35dee 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -1437,21 +1437,33 @@ const struct user_regset_view *task_user #endif } -void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, - int error_code, int si_code) +static void fill_sigtrap_info(struct task_struct *tsk, + struct pt_regs *regs, + int error_code, int si_code, + struct siginfo *info) { - struct siginfo info; - tsk->thread.trap_no = 1; tsk->thread.error_code = error_code; - memset(&info, 0, sizeof(info)); - info.si_signo = SIGTRAP; - info.si_code = si_code; + memset(info, 0, sizeof(*info)); + info->si_signo = SIGTRAP; + info->si_code = si_code; + info->si_addr = user_mode_vm(regs) ? (void __user *)regs->ip : NULL; +} - /* User-mode ip? */ - info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL; +void user_single_step_siginfo(struct task_struct *tsk, + struct pt_regs *regs, + struct siginfo *info) +{ + fill_sigtrap_info(tsk, regs, 0, TRAP_BRKPT, info); +} + +void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, + int error_code, int si_code) +{ + struct siginfo info; + fill_sigtrap_info(tsk, regs, error_code, si_code, &info); /* Send us the fake SIGTRAP */ force_sig_info(SIGTRAP, &info, tsk); } @@ -1516,29 +1528,22 @@ asmregparm long syscall_trace_enter(stru asmregparm void syscall_trace_leave(struct pt_regs *regs) { + bool step; + if (unlikely(current->audit_context)) audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax); if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) trace_sys_exit(regs, regs->ax); - if (test_thread_flag(TIF_SYSCALL_TRACE)) - tracehook_report_syscall_exit(regs, 0); - /* * If TIF_SYSCALL_EMU is set, we only get here because of * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP). * We already reported this syscall instruction in - * syscall_trace_enter(), so don't do any more now. - */ - if (unlikely(test_thread_flag(TIF_SYSCALL_EMU))) - return; - - /* - * If we are single-stepping, synthesize a trap to follow the - * system call instruction. + * syscall_trace_enter(). */ - if (test_thread_flag(TIF_SINGLESTEP) && - tracehook_consider_fatal_signal(current, SIGTRAP)) - send_sigtrap(current, regs, 0, TRAP_BRKPT); + step = unlikely(test_thread_flag(TIF_SINGLESTEP)) && + !test_thread_flag(TIF_SYSCALL_EMU); + if (step || test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall_exit(regs, step); } diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 7456d7d..4802e2a 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -85,6 +85,7 @@ extern int ptrace_traceme(void); extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len); extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len); extern int ptrace_attach(struct task_struct *tsk); +extern bool __ptrace_detach(struct task_struct *tracer, struct task_struct *tracee); extern int ptrace_detach(struct task_struct *, unsigned int); extern void ptrace_disable(struct task_struct *); extern int ptrace_check_attach(struct task_struct *task, int kill); @@ -105,12 +106,7 @@ static inline int ptrace_reparented(stru { return child->real_parent != child->parent; } -static inline void ptrace_link(struct task_struct *child, - struct task_struct *new_parent) -{ - if (unlikely(child->ptrace)) - __ptrace_link(child, new_parent); -} + static inline void ptrace_unlink(struct task_struct *child) { if (unlikely(child->ptrace)) @@ -169,9 +165,9 @@ static inline void ptrace_init_task(stru INIT_LIST_HEAD(&child->ptraced); child->parent = child->real_parent; child->ptrace = 0; - if (unlikely(ptrace)) { + if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) { child->ptrace = current->ptrace; - ptrace_link(child, current->parent); + __ptrace_link(child, current->parent); } } @@ -278,6 +274,18 @@ static inline void user_enable_block_ste } #endif /* arch_has_block_step */ +#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO +extern void user_single_step_siginfo(struct task_struct *tsk, + struct pt_regs *regs, siginfo_t *info); +#else +static inline void user_single_step_siginfo(struct task_struct *tsk, + struct pt_regs *regs, siginfo_t *info) +{ + memset(info, 0, sizeof(*info)); + info->si_signo = SIGTRAP; +} +#endif + #ifndef arch_ptrace_stop_needed /** * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called diff --git a/include/linux/sched.h b/include/linux/sched.h index 75e6e60..6c8928b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2060,6 +2060,7 @@ extern int kill_pgrp(struct pid *pid, in extern int kill_pid(struct pid *pid, int sig, int priv); extern int kill_proc_info(int, struct siginfo *, pid_t); extern int do_notify_parent(struct task_struct *, int); +extern void do_notify_parent_cldstop(struct task_struct *, int); extern void __wake_up_parent(struct task_struct *p, struct task_struct *parent); extern void force_sig(int, struct task_struct *); extern void force_sig_specific(int, struct task_struct *); diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 1eb44a9..c78b2f4 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -134,6 +134,13 @@ static inline __must_check int tracehook */ static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step) { + if (step && (task_ptrace(current) & PT_PTRACED)) { + siginfo_t info; + user_single_step_siginfo(current, regs, &info); + force_sig_info(SIGTRAP, &info, current); + return; + } + ptrace_report_syscall(regs); } @@ -149,7 +156,7 @@ static inline int tracehook_unsafe_exec( { int unsafe = 0; int ptrace = task_ptrace(task); - if (ptrace & PT_PTRACED) { + if (ptrace) { if (ptrace & PT_PTRACE_CAP) unsafe |= LSM_UNSAFE_PTRACE_CAP; else @@ -171,7 +178,7 @@ static inline int tracehook_unsafe_exec( */ static inline struct task_struct *tracehook_tracer_task(struct task_struct *tsk) { - if (task_ptrace(tsk) & PT_PTRACED) + if (task_ptrace(tsk)) return rcu_dereference(tsk->parent); return NULL; } @@ -379,7 +386,7 @@ static inline void tracehook_signal_hand const struct k_sigaction *ka, struct pt_regs *regs, int stepping) { - if (stepping) + if (stepping && (task_ptrace(current) & PT_PTRACED)) ptrace_notify(SIGTRAP); } @@ -485,7 +492,7 @@ static inline int tracehook_get_signal(s */ static inline int tracehook_notify_jctl(int notify, int why) { - return notify ?: (current->ptrace & PT_PTRACED) ? why : 0; + return notify ?: task_ptrace(current) ? why : 0; } /** diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 23bd09c..b7c1d32 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -271,7 +271,7 @@ static int ignoring_children(struct sigh * reap it now, in that case we must also wake up sub-threads sleeping in * do_wait(). */ -static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) +bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) { __ptrace_unlink(p); diff --git a/kernel/signal.c b/kernel/signal.c index 6705320..9908335 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1461,7 +1461,7 @@ int do_notify_parent(struct task_struct return ret; } -static void do_notify_parent_cldstop(struct task_struct *tsk, int why) +void do_notify_parent_cldstop(struct task_struct *tsk, int why) { struct siginfo info; unsigned long flags; @@ -1731,7 +1731,7 @@ static int do_signal_stop(int signr) static int ptrace_signal(int signr, siginfo_t *info, struct pt_regs *regs, void *cookie) { - if (!task_ptrace(current)) + if (!(task_ptrace(current) & PT_PTRACED)) return signr; ptrace_signal_deliver(regs, cookie); @@ -1807,11 +1807,6 @@ relock: for (;;) { struct k_sigaction *ka; - - if (unlikely(signal->group_stop_count > 0) && - do_signal_stop(0)) - goto relock; - /* * Tracing can induce an artifical signal and choose sigaction. * The return value in @signr determines the default action, @@ -1823,6 +1818,10 @@ relock: if (unlikely(signr != 0)) ka = return_ka; else { + if (unlikely(signal->group_stop_count > 0) && + do_signal_stop(0)) + goto relock; + signr = dequeue_signal(current, ¤t->blocked, info);