diff options
Diffstat (limited to 'kernel/trace/trace_syscalls.c')
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 44 |
1 files changed, 36 insertions, 8 deletions
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 58b8e5370767..51213b0aa81b 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -477,6 +477,7 @@ static int sys_prof_refcount_exit; static void prof_syscall_enter(struct pt_regs *regs, long id) { struct syscall_metadata *sys_data; + struct perf_trace_buf *trace_buf; struct syscall_trace_enter *rec; unsigned long flags; char *raw_data; @@ -507,14 +508,25 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) cpu = smp_processor_id(); if (in_nmi()) - raw_data = rcu_dereference(trace_profile_buf_nmi); + trace_buf = rcu_dereference(perf_trace_buf_nmi); else - raw_data = rcu_dereference(trace_profile_buf); + trace_buf = rcu_dereference(perf_trace_buf); - if (!raw_data) + if (!trace_buf) goto end; - raw_data = per_cpu_ptr(raw_data, cpu); + trace_buf = per_cpu_ptr(trace_buf, cpu); + + if (trace_buf->recursion++) + goto end_recursion; + + /* + * Make recursion update visible before entering perf_tp_event + * so that we protect from perf recursions. + */ + barrier(); + + raw_data = trace_buf->buf; /* zero the dead bytes from align to not leak stack to user */ *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; @@ -527,6 +539,8 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) (unsigned long *)&rec->args); perf_tp_event(sys_data->enter_id, 0, 1, rec, size); +end_recursion: + trace_buf->recursion--; end: local_irq_restore(flags); } @@ -574,6 +588,7 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) { struct syscall_metadata *sys_data; struct syscall_trace_exit *rec; + struct perf_trace_buf *trace_buf; unsigned long flags; int syscall_nr; char *raw_data; @@ -605,14 +620,25 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) cpu = smp_processor_id(); if (in_nmi()) - raw_data = rcu_dereference(trace_profile_buf_nmi); + trace_buf = rcu_dereference(perf_trace_buf_nmi); else - raw_data = rcu_dereference(trace_profile_buf); + trace_buf = rcu_dereference(perf_trace_buf); - if (!raw_data) + if (!trace_buf) goto end; - raw_data = per_cpu_ptr(raw_data, cpu); + trace_buf = per_cpu_ptr(trace_buf, cpu); + + if (trace_buf->recursion++) + goto end_recursion; + + /* + * Make recursion update visible before entering perf_tp_event + * so that we protect from perf recursions. + */ + barrier(); + + raw_data = trace_buf->buf; /* zero the dead bytes from align to not leak stack to user */ *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; @@ -626,6 +652,8 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) perf_tp_event(sys_data->exit_id, 0, 1, rec, size); +end_recursion: + trace_buf->recursion--; end: local_irq_restore(flags); } |