From 88ebe8cc196069ec1997a5ce61943c209be894d4 Mon Sep 17 00:00:00 2001 From: Athira Rajeev Date: Sun, 23 Jun 2024 12:18:48 +0530 Subject: [PATCH] tools/perf: Fix the string match for "/tmp/perf-$PID.map" files in dso__load BugLink: https://bugs.launchpad.net/bugs/2083196 [ Upstream commit b0979f008f1352a44cd3c8877e3eb8a1e3e1c6f3 ] Perf test for perf probe of function from different CU fails as below: ./perf test -vv "test perf probe of function from different CU" 116: test perf probe of function from different CU: --- start --- test child forked, pid 2679 Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.Msa7iy89bx/testfile Error: Failed to add events. --- Cleaning up --- "foo" does not hit any event. Error: Failed to delete events. ---- end(-1) ---- 116: test perf probe of function from different CU : FAILED! The test does below to probe function "foo" : # gcc -g -Og -flto -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.c -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o # gcc -g -Og -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.c -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o # gcc -g -Og -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o # ./perf probe -x /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile foo Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile Error: Failed to add events. Perf probe fails to find symbol foo in the executable placed in /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7 Simple reproduce: # mktemp -d /tmp/perf-checkXXXXXXXXXX /tmp/perf-checkcWpuLRQI8j # gcc -g -o test test.c # cp test /tmp/perf-checkcWpuLRQI8j/ # nm /tmp/perf-checkcWpuLRQI8j/test | grep foo 00000000100006bc T foo # ./perf probe -x /tmp/perf-checkcWpuLRQI8j/test foo Failed to find symbol foo in /tmp/perf-checkcWpuLRQI8j/test Error: Failed to add events. But it works with any files like /tmp/perf/test. Only for patterns with "/tmp/perf-", this fails. Further debugging, commit 80d496be89ed ("perf report: Add support for profiling JIT generated code") added support for profiling JIT generated code. This patch handles dso's of form "/tmp/perf-$PID.map" . The check used "if (strncmp(self->name, "/tmp/perf-", 10) == 0)" to match "/tmp/perf-$PID.map". With this commit, any dso in /tmp/perf- folder will be considered separately for processing (not only JIT created map files ). Fix this by changing the string pattern to check for "/tmp/perf-%d.map". Add a helper function is_perf_pid_map_name to do this check. In "struct dso", dso->long_name holds the long name of the dso file. Since the /tmp/perf-$PID.map check uses the complete name, use dso___long_name for the string name. With the fix, # ./perf test "test perf probe of function from different CU" 117: test perf probe of function from different CU : Ok Fixes: 56cbeacf1435 ("perf probe: Add test for regression introduced by switch to die_get_decl_file()") Signed-off-by: Athira Rajeev Reviewed-by: Chaitanya S Prakash Reviewed-by: Adrian Hunter Cc: akanksha@linux.ibm.com Cc: kjain@linux.ibm.com Cc: maddy@linux.ibm.com Cc: disgoel@linux.vnet.ibm.com Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240623064850.83720-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Sasha Levin Signed-off-by: Portia Stephens Signed-off-by: Roxana Nicolescu --- tools/perf/util/dso.c | 12 ++++++++++++ tools/perf/util/dso.h | 4 ++++ tools/perf/util/symbol.c | 2 +- 3 files changed, 17 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index 22fd5fa806ed..4ab1b03d0779 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -1532,3 +1532,15 @@ int dso__strerror_load(struct dso *dso, char *buf, size_t buflen) scnprintf(buf, buflen, "%s", dso_load__error_str[idx]); return 0; } + +bool perf_pid_map_tid(const char *dso_name, int *tid) +{ + return sscanf(dso_name, "/tmp/perf-%d.map", tid) == 1; +} + +bool is_perf_pid_map_name(const char *dso_name) +{ + int tid; + + return perf_pid_map_tid(dso_name, &tid); +} diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h index ce9f3849a773..f161ac10fa03 100644 --- a/tools/perf/util/dso.h +++ b/tools/perf/util/dso.h @@ -411,4 +411,8 @@ int dso__strerror_load(struct dso *dso, char *buf, size_t buflen); void reset_fd_limit(void); +/* Check if dso name is of format "/tmp/perf-%d.map" */ +bool perf_pid_map_tid(const char *dso_name, int *tid); +bool is_perf_pid_map_name(const char *dso_name); + #endif /* __PERF_DSO */ diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 8e09f7db933a..85679aa443f3 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1764,7 +1764,7 @@ int dso__load(struct dso *dso, struct map *map) const char *map_path = dso->long_name; mutex_lock(&dso->lock); - perfmap = strncmp(dso->name, "/tmp/perf-", 10) == 0; + perfmap = is_perf_pid_map_name(map_path); if (perfmap) { if (dso->nsinfo && (dso__find_perf_map(newmapname, sizeof(newmapname), &dso->nsinfo) == 0)) {