From 86758d5f2b838d5769c7ace15269a4ebc422f94a Mon Sep 17 00:00:00 2001 From: Josh Stone Date: Mon, 16 Mar 2009 18:13:07 -0700 Subject: Fix regression in tracepoint unregistration Commit 96b030fe reorganized the tracepoint registration calls by creating generic wrappers that return int. However, the older tracepoint implementation (as found in RHEL5.3) returned void for unreg, so this was failing pass-4. Since we can't handle unregistration failures anyway, this change just makes the generic unregister function return void instead. As noted in the newly-added comment, it should be safe for us to ignore unreg failures. --- tapsets.cxx | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/tapsets.cxx b/tapsets.cxx index 6efcb3af..2f940b29 100644 --- a/tapsets.cxx +++ b/tapsets.cxx @@ -9770,8 +9770,13 @@ tracepoint_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->newline(1) << "return register_trace_" << p->tracepoint_name << "(enter_tracepoint_probe_" << i << ");"; s.op->newline(-1) << "}"; - s.op->newline() << "static int unregister_tracepoint_probe_" << i << "(void) {"; - s.op->newline(1) << "return unregister_trace_" << p->tracepoint_name + + // NB: we're not prepared to deal with unreg failures. However, failures + // can only occur if the tracepoint doesn't exist (yet?), or if we + // weren't even registered. The former should be OKed by the initial + // registration call, and the latter is safe to ignore. + s.op->newline() << "static void unregister_tracepoint_probe_" << i << "(void) {"; + s.op->newline(1) << "(void) unregister_trace_" << p->tracepoint_name << "(enter_tracepoint_probe_" << i << ");"; s.op->newline(-1) << "}"; s.op->newline(); @@ -9780,7 +9785,7 @@ tracepoint_derived_probe_group::emit_module_decls (systemtap_session& s) // emit an array of registration functions for easy init/shutdown s.op->newline() << "static struct stap_tracepoint_probe {"; s.op->newline(1) << "int (*reg)(void);"; - s.op->newline(0) << "int (*unreg)(void);"; + s.op->newline(0) << "void (*unreg)(void);"; s.op->newline(-1) << "} stap_tracepoint_probes[] = {"; s.op->indent(1); for (unsigned i = 0; i < probes.size(); ++i) -- cgit From 924a2ea21d0276229a752e58e5c5c1a9346648be Mon Sep 17 00:00:00 2001 From: Josh Stone Date: Mon, 16 Mar 2009 18:36:44 -0700 Subject: PR9951: Prevent GCC warnings in deref() In some configurations, GCC was warning about a possible use of _v in the deref macros. I could not reproduce the error, but the only case where _v is not written is if lookup_bad_addr rejects the address, in which case we will hit DEREF_FAULT and _v won't be used. Now we're priming _v=0 anyway, so GCC has no right to complain... --- runtime/loc2c-runtime.h | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/runtime/loc2c-runtime.h b/runtime/loc2c-runtime.h index 92c017d3..16ddb950 100644 --- a/runtime/loc2c-runtime.h +++ b/runtime/loc2c-runtime.h @@ -186,7 +186,7 @@ */ #define kread(ptr) ({ \ - typeof(*(ptr)) _v; \ + typeof(*(ptr)) _v = 0; \ if (lookup_bad_addr((unsigned long)(ptr)) || \ probe_kernel_read((void *)&_v, (void *)(ptr), sizeof(*(ptr)))) \ DEREF_FAULT(ptr); \ @@ -202,14 +202,13 @@ }) #define deref(size, addr) ({ \ - intptr_t _i; \ + intptr_t _i = 0; \ switch (size) { \ case 1: _i = kread((u8 *)(addr)); break; \ case 2: _i = kread((u16 *)(addr)); break; \ case 4: _i = kread((u32 *)(addr)); break; \ case 8: _i = kread((u64 *)(addr)); break; \ default: __deref_bad(); \ - /* uninitialized _i should also be caught by -Werror */ \ } \ _i; \ }) @@ -235,7 +234,7 @@ extern void __store_deref_bad(void); ({ \ int _bad = 0; \ u8 _b; u16 _w; u32 _l; \ - intptr_t _v; \ + intptr_t _v = 0; \ if (lookup_bad_addr((unsigned long)addr)) \ _bad = 1; \ else \ @@ -275,7 +274,7 @@ extern void __store_deref_bad(void); ({ \ int _bad = 0; \ u8 _b; u16 _w; u32 _l; u64 _q; \ - intptr_t _v; \ + intptr_t _v = 0; \ if (lookup_bad_addr((unsigned long)addr)) \ _bad = 1; \ else \ @@ -392,7 +391,7 @@ extern void __store_deref_bad(void); #define deref(size, addr) \ ({ \ int _bad = 0; \ - intptr_t _v; \ + intptr_t _v = 0; \ if (lookup_bad_addr((unsigned long)addr)) \ _bad = 1; \ else \ -- cgit From bdca08879745471fdb86991a8e7276900aaaf066 Mon Sep 17 00:00:00 2001 From: Wenji Huang Date: Mon, 16 Mar 2009 18:21:41 -0400 Subject: Add pid-based data lookup function. Two functions pid2task and pid2execname. --- tapset/task.stp | 24 ++++++++++++++++++++++++ testsuite/buildok/task-embedded.stp | 4 +++- testsuite/buildok/task_test.stp | 2 ++ 3 files changed, 29 insertions(+), 1 deletion(-) diff --git a/tapset/task.stp b/tapset/task.stp index 07337156..f1a10b0a 100644 --- a/tapset/task.stp +++ b/tapset/task.stp @@ -63,6 +63,30 @@ function task_pid:long (task:long) } +// Return the task of the given process id +function pid2task:long (pid:long) %{ /* pure */ + struct task_struct *t = NULL; + pid_t t_pid = (pid_t)(long)THIS->pid; + rcu_read_lock(); +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24) + t = find_task_by_vpid (t_pid); +#else + t = find_task_by_pid (t_pid); +#endif + rcu_read_unlock(); + THIS->__retvalue = (long)t; + CATCH_DEREF_FAULT(); +%} + +// Return the name of the given process id +function pid2execname:string (pid:long) { + tsk = pid2task(pid) + if (tsk) + return task_execname(tsk) + return "" +} + + // Return the thread id of the given task function task_tid:long (task:long) { diff --git a/testsuite/buildok/task-embedded.stp b/testsuite/buildok/task-embedded.stp index 4d1f5300..d35f3e0d 100755 --- a/testsuite/buildok/task-embedded.stp +++ b/testsuite/buildok/task-embedded.stp @@ -14,6 +14,8 @@ probe begin { task_nice (0) + task_cpu (0) + task_open_file_handles (0) + - task_max_file_handles (0)) + task_max_file_handles (0) + + pid2task(0)) print (task_execname (0)) + print (pid2execname (0)) } diff --git a/testsuite/buildok/task_test.stp b/testsuite/buildok/task_test.stp index c8da7da5..792f96ea 100755 --- a/testsuite/buildok/task_test.stp +++ b/testsuite/buildok/task_test.stp @@ -16,5 +16,7 @@ probe begin { log(sprint(task_cpu(c))) log(sprint(task_open_file_handles(c))) log(sprint(task_max_file_handles(c))) + log(sprint(pid2task(pid()))) + log(sprint(pid2execname(pid()))) exit() } -- cgit