Message ID | 29cf4df8950a06184aa510fec6f2ac1333fd5c0d.1620838411.git.fweimer@redhat.com |
---|---|
State | New |
Headers | show |
Series | nptl: Move almost all remaining functions into libc | expand |
On 12/05/2021 13:57, Florian Weimer via Libc-alpha wrote: > The initialization of the report_events TCB field is now performed > in __tls_init_tp instead of __pthread_initialize_minimal_internal > (in libpthread). > > The events interface is difficult to test becaue GDB stopped using it s/becaue/because > in 2015. The td_thr_get_info change to ingore lookup issues is s/ingore/ignore > enough to support GDB with this change. Should we start to deprecate and remove such interfaces? Your patch is already ignoring the possible error on td_thr_get_info. Not sure how backwards compatible regarding debugging interface we should be. Regardless, it looks good to me. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > nptl/Versions | 1 + > nptl/nptl-init.c | 12 ------------ > nptl/pthreadP.h | 5 +++++ > nptl_db/db_info.c | 3 --- > nptl_db/structs.def | 2 +- > nptl_db/td_thr_get_info.c | 11 +++++++++-- > sysdeps/nptl/dl-tls_init_tp.c | 8 ++++++++ > 7 files changed, 24 insertions(+), 18 deletions(-) > > diff --git a/nptl/Versions b/nptl/Versions > index 1dd3fbc18c..fb3379b788 100644 > --- a/nptl/Versions > +++ b/nptl/Versions > @@ -497,6 +497,7 @@ libpthread { > > ld { > GLIBC_PRIVATE { > + __nptl_initial_report_events; > __nptl_set_robust_list_avail; > } > } > \ No newline at end of file Ok. > diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c > index 16fb66bdf5..f4b86fbfaf 100644 > --- a/nptl/nptl-init.c > +++ b/nptl/nptl-init.c > @@ -96,21 +96,9 @@ sigcancel_handler (int sig, siginfo_t *si, void *ctx) > extern void **__libc_dl_error_tsd (void) __attribute__ ((const)); > > > -/* This can be set by the debugger before initialization is complete. */ > -static bool __nptl_initial_report_events __attribute_used__; > - > void > __pthread_initialize_minimal_internal (void) > { > - /* Partial initialization of the TCB already happened in TLS_INIT_TP > - and __tls_init_tp. */ > - struct pthread *pd = THREAD_SELF; > - > - /* Before initializing GL (dl_stack_user), the debugger could not > - find us and had to set __nptl_initial_report_events. Propagate > - its setting. */ > - THREAD_SETMEM (pd, report_events, __nptl_initial_report_events); > - > struct sigaction sa; > __sigemptyset (&sa.sa_mask); > Ok. > diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h > index 5b844f331a..dc2aece37e 100644 > --- a/nptl/pthreadP.h > +++ b/nptl/pthreadP.h > @@ -328,6 +328,11 @@ extern int __pthread_attr_init (pthread_attr_t *attr); > libc_hidden_proto (__pthread_attr_init) > extern int __pthread_attr_init_2_0 (pthread_attr_t *attr); > > +/* Part of the legacy thread events interface (which has been > + superseded by PTRACE_O_TRACECLONE). This can be set by the > + debugger before initialization is complete. */ > +extern bool __nptl_initial_report_events; > +rtld_hidden_proto (__nptl_initial_report_events) > > /* Event handlers for libthread_db interface. */ > extern void __nptl_create_event (void); Ok. > diff --git a/nptl_db/db_info.c b/nptl_db/db_info.c > index bed6ed486e..b39aebb78c 100644 > --- a/nptl_db/db_info.c > +++ b/nptl_db/db_info.c > @@ -42,9 +42,6 @@ typedef struct rtld_global rtld_global; > typedef struct dtv_slotinfo_list dtv_slotinfo_list; > typedef struct dtv_slotinfo dtv_slotinfo; > > -/* Actually static in nptl/init.c, but we only need it for typeof. */ > -extern bool __nptl_initial_report_events; > - > #define schedparam_sched_priority schedparam.sched_priority > > #define eventbuf_eventmask eventbuf.eventmask Ok. > diff --git a/nptl_db/structs.def b/nptl_db/structs.def > index 9173e1ab8f..275c12bc7a 100644 > --- a/nptl_db/structs.def > +++ b/nptl_db/structs.def > @@ -80,7 +80,7 @@ DB_FUNCTION (__nptl_death_event) > DB_SYMBOL (__nptl_threads_events) > DB_MAIN_VARIABLE (__nptl_nthreads) > DB_VARIABLE (__nptl_last_event) > -DB_VARIABLE (__nptl_initial_report_events) > +DB_RTLD_VARIABLE (__nptl_initial_report_events) > > DB_MAIN_ARRAY_VARIABLE (__pthread_keys) > DB_STRUCT (pthread_key_struct) Ok. > diff --git a/nptl_db/td_thr_get_info.c b/nptl_db/td_thr_get_info.c > index 002a22a5be..01af021d2a 100644 > --- a/nptl_db/td_thr_get_info.c > +++ b/nptl_db/td_thr_get_info.c > @@ -41,8 +41,15 @@ td_thr_get_info (const td_thrhandle_t *th, td_thrinfo_t *infop) > schedpolicy = SCHED_OTHER; > schedprio = 0; > tid = 0; > - err = DB_GET_VALUE (report_events, th->th_ta_p, > - __nptl_initial_report_events, 0); > + > + /* Ignore errors to obtain the __nptl_initial_report_events > + value because GDB no longer uses the events interface, and > + other libthread_db consumers hopefully can handle different > + libpthread/lds.o load orders. */ > + report_events = 0; > + (void) DB_GET_VALUE (report_events, th->th_ta_p, > + __nptl_initial_report_events, 0); > + err = TD_OK; > } > else > { Ok. > diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c > index f1aaa5aa9d..1f7790297f 100644 > --- a/sysdeps/nptl/dl-tls_init_tp.c > +++ b/sysdeps/nptl/dl-tls_init_tp.c > @@ -27,6 +27,9 @@ bool __nptl_set_robust_list_avail __attribute__ ((nocommon)); > rtld_hidden_data_def (__nptl_set_robust_list_avail) > #endif > > +bool __nptl_initial_report_events __attribute__ ((nocommon)); > +rtld_hidden_def (__nptl_initial_report_events) > + > #ifdef SHARED > /* Dummy implementation. See __rtld_mutex_init. */ > static int > @@ -63,6 +66,11 @@ __tls_init_tp (void) > THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]); > THREAD_SETMEM (pd, user_stack, true); > > + /* Before initializing GL (dl_stack_user), the debugger could not > + find us and had to set __nptl_initial_report_events. Propagate > + its setting. */ > + THREAD_SETMEM (pd, report_events, __nptl_initial_report_events); > + > /* Initialize the robust mutex data. */ > { > #if __PTHREAD_MUTEX_HAVE_PREV > Ok.
* Adhemerval Zanella via Libc-alpha: >> enough to support GDB with this change. > > Should we start to deprecate and remove such interfaces? Your patch is > already ignoring the possible error on td_thr_get_info. I think we should deprecate these interfaces. The dyninst framework may still be using them (it's hard to tell based on the source code). There are other libthread_db interfaces that aren't used by GDB (they pthread_key_t handling comes to my mind). Thanks, Florian
On 17/05/2021 05:06, Florian Weimer wrote: > * Adhemerval Zanella via Libc-alpha: > >>> enough to support GDB with this change. >> >> Should we start to deprecate and remove such interfaces? Your patch is >> already ignoring the possible error on td_thr_get_info. > > I think we should deprecate these interfaces. The dyninst framework may > still be using them (it's hard to tell based on the source code). > > There are other libthread_db interfaces that aren't used by GDB (they > pthread_key_t handling comes to my mind). OK, I think we can start to deprecate them on new version. Maybe we can even remove it, since I hardly think this interface is worth to keep as a compatibility layer.
diff --git a/nptl/Versions b/nptl/Versions index 1dd3fbc18c..fb3379b788 100644 --- a/nptl/Versions +++ b/nptl/Versions @@ -497,6 +497,7 @@ libpthread { ld { GLIBC_PRIVATE { + __nptl_initial_report_events; __nptl_set_robust_list_avail; } } \ No newline at end of file diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c index 16fb66bdf5..f4b86fbfaf 100644 --- a/nptl/nptl-init.c +++ b/nptl/nptl-init.c @@ -96,21 +96,9 @@ sigcancel_handler (int sig, siginfo_t *si, void *ctx) extern void **__libc_dl_error_tsd (void) __attribute__ ((const)); -/* This can be set by the debugger before initialization is complete. */ -static bool __nptl_initial_report_events __attribute_used__; - void __pthread_initialize_minimal_internal (void) { - /* Partial initialization of the TCB already happened in TLS_INIT_TP - and __tls_init_tp. */ - struct pthread *pd = THREAD_SELF; - - /* Before initializing GL (dl_stack_user), the debugger could not - find us and had to set __nptl_initial_report_events. Propagate - its setting. */ - THREAD_SETMEM (pd, report_events, __nptl_initial_report_events); - struct sigaction sa; __sigemptyset (&sa.sa_mask); diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index 5b844f331a..dc2aece37e 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -328,6 +328,11 @@ extern int __pthread_attr_init (pthread_attr_t *attr); libc_hidden_proto (__pthread_attr_init) extern int __pthread_attr_init_2_0 (pthread_attr_t *attr); +/* Part of the legacy thread events interface (which has been + superseded by PTRACE_O_TRACECLONE). This can be set by the + debugger before initialization is complete. */ +extern bool __nptl_initial_report_events; +rtld_hidden_proto (__nptl_initial_report_events) /* Event handlers for libthread_db interface. */ extern void __nptl_create_event (void); diff --git a/nptl_db/db_info.c b/nptl_db/db_info.c index bed6ed486e..b39aebb78c 100644 --- a/nptl_db/db_info.c +++ b/nptl_db/db_info.c @@ -42,9 +42,6 @@ typedef struct rtld_global rtld_global; typedef struct dtv_slotinfo_list dtv_slotinfo_list; typedef struct dtv_slotinfo dtv_slotinfo; -/* Actually static in nptl/init.c, but we only need it for typeof. */ -extern bool __nptl_initial_report_events; - #define schedparam_sched_priority schedparam.sched_priority #define eventbuf_eventmask eventbuf.eventmask diff --git a/nptl_db/structs.def b/nptl_db/structs.def index 9173e1ab8f..275c12bc7a 100644 --- a/nptl_db/structs.def +++ b/nptl_db/structs.def @@ -80,7 +80,7 @@ DB_FUNCTION (__nptl_death_event) DB_SYMBOL (__nptl_threads_events) DB_MAIN_VARIABLE (__nptl_nthreads) DB_VARIABLE (__nptl_last_event) -DB_VARIABLE (__nptl_initial_report_events) +DB_RTLD_VARIABLE (__nptl_initial_report_events) DB_MAIN_ARRAY_VARIABLE (__pthread_keys) DB_STRUCT (pthread_key_struct) diff --git a/nptl_db/td_thr_get_info.c b/nptl_db/td_thr_get_info.c index 002a22a5be..01af021d2a 100644 --- a/nptl_db/td_thr_get_info.c +++ b/nptl_db/td_thr_get_info.c @@ -41,8 +41,15 @@ td_thr_get_info (const td_thrhandle_t *th, td_thrinfo_t *infop) schedpolicy = SCHED_OTHER; schedprio = 0; tid = 0; - err = DB_GET_VALUE (report_events, th->th_ta_p, - __nptl_initial_report_events, 0); + + /* Ignore errors to obtain the __nptl_initial_report_events + value because GDB no longer uses the events interface, and + other libthread_db consumers hopefully can handle different + libpthread/lds.o load orders. */ + report_events = 0; + (void) DB_GET_VALUE (report_events, th->th_ta_p, + __nptl_initial_report_events, 0); + err = TD_OK; } else { diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c index f1aaa5aa9d..1f7790297f 100644 --- a/sysdeps/nptl/dl-tls_init_tp.c +++ b/sysdeps/nptl/dl-tls_init_tp.c @@ -27,6 +27,9 @@ bool __nptl_set_robust_list_avail __attribute__ ((nocommon)); rtld_hidden_data_def (__nptl_set_robust_list_avail) #endif +bool __nptl_initial_report_events __attribute__ ((nocommon)); +rtld_hidden_def (__nptl_initial_report_events) + #ifdef SHARED /* Dummy implementation. See __rtld_mutex_init. */ static int @@ -63,6 +66,11 @@ __tls_init_tp (void) THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]); THREAD_SETMEM (pd, user_stack, true); + /* Before initializing GL (dl_stack_user), the debugger could not + find us and had to set __nptl_initial_report_events. Propagate + its setting. */ + THREAD_SETMEM (pd, report_events, __nptl_initial_report_events); + /* Initialize the robust mutex data. */ { #if __PTHREAD_MUTEX_HAVE_PREV