Date: Tue, 8 Mar 2016 00:43:04 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r296479 - in head/sys/cddl/contrib/opensolaris/uts: common/dtrace common/sys intel/dtrace powerpc/dtrace Message-ID: <201603080043.u280h46P042051@repo.freebsd.org>
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Author: markj Date: Tue Mar 8 00:43:03 2016 New Revision: 296479 URL: https://svnweb.freebsd.org/changeset/base/296479 Log: Fix fasttrap tracepoint locking. Upstream, tracepoints are protected by per-CPU mutexes. An unlinked tracepoint may be freed once all the tracepoint mutexes have been acquired and released - this is done in fasttrap_mod_barrier(). This mechanism was not properly ported: in some places, the proc lock is used in place of a tracepoint lock, and in others the locking is omitted entirely. This change implements tracepoint locking with an rmlock, where the read lock is used in fasttrap probe context. As a side effect, this fixes a recursion on the proc lock when the raise action is used from a userland probe. MFC after: 1 month Modified: head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c head/sys/cddl/contrib/opensolaris/uts/common/sys/fasttrap_impl.h head/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c head/sys/cddl/contrib/opensolaris/uts/powerpc/dtrace/fasttrap_isa.c Modified: head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c Tue Mar 8 00:23:56 2016 (r296478) +++ head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c Tue Mar 8 00:43:03 2016 (r296479) @@ -63,13 +63,16 @@ #ifndef illumos #include <sys/dtrace_bsd.h> #include <sys/eventhandler.h> +#include <sys/rmlock.h> #include <sys/sysctl.h> #include <sys/u8_textprep.h> #include <sys/user.h> + #include <vm/vm.h> #include <vm/pmap.h> #include <vm/vm_map.h> #include <vm/vm_param.h> + #include <cddl/dev/dtrace/dtrace_cddl.h> #endif @@ -224,7 +227,7 @@ static void fasttrap_thread_dtor(void *, #define FASTTRAP_PROCS_INDEX(pid) ((pid) & fasttrap_procs.fth_mask) #ifndef illumos -static kmutex_t fasttrap_cpuc_pid_lock[MAXCPU]; +struct rmlock fasttrap_tp_lock; static eventhandler_tag fasttrap_thread_dtor_tag; #endif @@ -439,10 +442,15 @@ fasttrap_mod_barrier(uint64_t gen) fasttrap_mod_gen++; +#ifdef illumos CPU_FOREACH(i) { mutex_enter(&fasttrap_cpuc_pid_lock[i]); mutex_exit(&fasttrap_cpuc_pid_lock[i]); } +#else + rm_wlock(&fasttrap_tp_lock); + rm_wunlock(&fasttrap_tp_lock); +#endif } /* @@ -2574,10 +2582,7 @@ fasttrap_load(void) mutex_init(&fasttrap_procs.fth_table[i].ftb_mtx, "processes bucket mtx", MUTEX_DEFAULT, NULL); - CPU_FOREACH(i) { - mutex_init(&fasttrap_cpuc_pid_lock[i], "fasttrap barrier", - MUTEX_DEFAULT, NULL); - } + rm_init(&fasttrap_tp_lock, "fasttrap tracepoint"); /* * This event handler must run before kdtrace_thread_dtor() since it @@ -2710,9 +2715,7 @@ fasttrap_unload(void) #ifndef illumos destroy_dev(fasttrap_cdev); mutex_destroy(&fasttrap_count_mtx); - CPU_FOREACH(i) { - mutex_destroy(&fasttrap_cpuc_pid_lock[i]); - } + rm_destroy(&fasttrap_tp_lock); #endif return (0); Modified: head/sys/cddl/contrib/opensolaris/uts/common/sys/fasttrap_impl.h ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/common/sys/fasttrap_impl.h Tue Mar 8 00:23:56 2016 (r296478) +++ head/sys/cddl/contrib/opensolaris/uts/common/sys/fasttrap_impl.h Tue Mar 8 00:43:03 2016 (r296479) @@ -206,6 +206,10 @@ extern fasttrap_scrspace_t *fasttrap_scr extern dtrace_id_t fasttrap_probe_id; extern fasttrap_hash_t fasttrap_tpoints; +#ifndef illumos +extern struct rmlock fasttrap_tp_lock; +#endif + #define FASTTRAP_TPOINTS_INDEX(pid, pc) \ (((pc) / sizeof (fasttrap_instr_t) + (pid)) & fasttrap_tpoints.fth_mask) Modified: head/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c Tue Mar 8 00:23:56 2016 (r296478) +++ head/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c Tue Mar 8 00:43:03 2016 (r296479) @@ -46,6 +46,7 @@ #include <cddl/dev/dtrace/dtrace_cddl.h> #include <sys/types.h> #include <sys/proc.h> +#include <sys/rmlock.h> #include <sys/dtrace_bsd.h> #include <cddl/dev/dtrace/x86/regset.h> #include <machine/segments.h> @@ -737,11 +738,13 @@ fasttrap_return_common(struct reg *rp, u fasttrap_id_t *id; #ifdef illumos kmutex_t *pid_mtx; -#endif -#ifdef illumos pid_mtx = &cpu_core[CPU->cpu_id].cpuc_pid_lock; mutex_enter(pid_mtx); +#else + struct rm_priotracker tracker; + + rm_rlock(&fasttrap_tp_lock, &tracker); #endif bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; @@ -759,6 +762,8 @@ fasttrap_return_common(struct reg *rp, u if (tp == NULL) { #ifdef illumos mutex_exit(pid_mtx); +#else + rm_runlock(&fasttrap_tp_lock, &tracker); #endif return; } @@ -782,6 +787,8 @@ fasttrap_return_common(struct reg *rp, u #ifdef illumos mutex_exit(pid_mtx); +#else + rm_runlock(&fasttrap_tp_lock, &tracker); #endif } @@ -990,6 +997,7 @@ fasttrap_pid_probe(struct reg *rp) { proc_t *p = curproc; #ifndef illumos + struct rm_priotracker tracker; proc_t *pp; #endif uintptr_t pc = rp->r_rip - 1; @@ -1049,8 +1057,7 @@ fasttrap_pid_probe(struct reg *rp) sx_sunlock(&proctree_lock); pp = NULL; - PROC_LOCK(p); - _PHOLD(p); + rm_rlock(&fasttrap_tp_lock, &tracker); #endif bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; @@ -1073,8 +1080,7 @@ fasttrap_pid_probe(struct reg *rp) #ifdef illumos mutex_exit(pid_mtx); #else - _PRELE(p); - PROC_UNLOCK(p); + rm_runlock(&fasttrap_tp_lock, &tracker); #endif return (-1); } @@ -1200,7 +1206,7 @@ fasttrap_pid_probe(struct reg *rp) #ifdef illumos mutex_exit(pid_mtx); #else - PROC_UNLOCK(p); + rm_runlock(&fasttrap_tp_lock, &tracker); #endif tp = &tp_local; @@ -1813,7 +1819,6 @@ done: #ifndef illumos PROC_LOCK(p); proc_write_regs(curthread, rp); - _PRELE(p); PROC_UNLOCK(p); #endif Modified: head/sys/cddl/contrib/opensolaris/uts/powerpc/dtrace/fasttrap_isa.c ============================================================================== --- head/sys/cddl/contrib/opensolaris/uts/powerpc/dtrace/fasttrap_isa.c Tue Mar 8 00:23:56 2016 (r296478) +++ head/sys/cddl/contrib/opensolaris/uts/powerpc/dtrace/fasttrap_isa.c Tue Mar 8 00:43:03 2016 (r296479) @@ -33,6 +33,7 @@ #include <sys/types.h> #include <sys/uio.h> #include <sys/ptrace.h> +#include <sys/rmlock.h> #include <sys/sysent.h> #define OP(x) ((x) >> 26) @@ -288,10 +289,12 @@ static void fasttrap_return_common(struct reg *rp, uintptr_t pc, pid_t pid, uintptr_t new_pc) { + struct rm_priotracker tracker; fasttrap_tracepoint_t *tp; fasttrap_bucket_t *bucket; fasttrap_id_t *id; + rm_rlock(&fasttrap_tp_lock, &tracker); bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) { @@ -306,6 +309,7 @@ fasttrap_return_common(struct reg *rp, u * is not essential to the correct execution of the process. */ if (tp == NULL) { + rm_runlock(&fasttrap_tp_lock, &tracker); return; } @@ -323,6 +327,7 @@ fasttrap_return_common(struct reg *rp, u pc - id->fti_probe->ftp_faddr, rp->fixreg[3], rp->fixreg[4], 0, 0); } + rm_runlock(&fasttrap_tp_lock, &tracker); } @@ -351,6 +356,7 @@ fasttrap_branch_taken(int bo, int bi, st int fasttrap_pid_probe(struct reg *rp) { + struct rm_priotracker tracker; proc_t *p = curproc; uintptr_t pc = rp->pc; uintptr_t new_pc = 0; @@ -381,8 +387,7 @@ fasttrap_pid_probe(struct reg *rp) curthread->t_dtrace_scrpc = 0; curthread->t_dtrace_astpc = 0; - - PROC_LOCK(p); + rm_rlock(&fasttrap_tp_lock, &tracker); pid = p->p_pid; bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; @@ -401,7 +406,7 @@ fasttrap_pid_probe(struct reg *rp) * fasttrap_ioctl), or somehow we have mislaid this tracepoint. */ if (tp == NULL) { - PROC_UNLOCK(p); + rm_runlock(&fasttrap_tp_lock, &tracker); return (-1); } @@ -455,7 +460,7 @@ fasttrap_pid_probe(struct reg *rp) * tracepoint again later if we need to light up any return probes. */ tp_local = *tp; - PROC_UNLOCK(p); + rm_runlock(&fasttrap_tp_lock, &tracker); tp = &tp_local; /*
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