From 31d1139956112dd047a70b263f4d578921de779a Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 17 Apr 2025 10:40:17 -0400 Subject: [PATCH 1/7] ftrace: Initialize variables for ftrace_startup/shutdown_subops() The reworking to fix and simplify the ftrace_startup_subops() and the ftrace_shutdown_subops() made it possible for the filter_hash and notrace_hash variables to be used uninitialized in a way that the compiler did not catch it. Initialize both filter_hash and notrace_hash to the EMPTY_HASH as that is what they should be if they never are used. Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20250417104017.3aea66c2@gandalf.local.home Reported-by: Venkat Rao Bagalkote Tested-by: Venkat Rao Bagalkote Fixes: 0ae6b8ce200d ("ftrace: Fix accounting of subop hashes") Closes: https://lore.kernel.org/all/1db64a42-626d-4b3a-be08-c65e47333ce2@linux.ibm.com/ Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a8a02868b435..43394445390c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3490,8 +3490,8 @@ static int add_next_hash(struct ftrace_hash **filter_hash, struct ftrace_hash ** */ int ftrace_startup_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int command) { - struct ftrace_hash *filter_hash; - struct ftrace_hash *notrace_hash; + struct ftrace_hash *filter_hash = EMPTY_HASH; + struct ftrace_hash *notrace_hash = EMPTY_HASH; struct ftrace_hash *save_filter_hash; struct ftrace_hash *save_notrace_hash; int ret; @@ -3625,8 +3625,8 @@ static int rebuild_hashes(struct ftrace_hash **filter_hash, struct ftrace_hash * */ int ftrace_shutdown_subops(struct ftrace_ops *ops, struct ftrace_ops *subops, int command) { - struct ftrace_hash *filter_hash; - struct ftrace_hash *notrace_hash; + struct ftrace_hash *filter_hash = EMPTY_HASH; + struct ftrace_hash *notrace_hash = EMPTY_HASH; int ret; if (unlikely(ftrace_disabled)) From 08275e59a75047ba8fc0b9853bfdfc88a124763d Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 17 Apr 2025 11:09:33 -0400 Subject: [PATCH 2/7] ftrace: Reinitialize hash to EMPTY_HASH after freeing There's several locations that free a ftrace hash pointer but may be referenced again. Reset them to EMPTY_HASH so that a u-a-f bug doesn't happen. Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20250417110933.20ab718b@gandalf.local.home Fixes: 0ae6b8ce200d ("ftrace: Fix accounting of subop hashes") Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 43394445390c..d0e4a902bb40 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1297,6 +1297,8 @@ void ftrace_free_filter(struct ftrace_ops *ops) return; free_ftrace_hash(ops->func_hash->filter_hash); free_ftrace_hash(ops->func_hash->notrace_hash); + ops->func_hash->filter_hash = EMPTY_HASH; + ops->func_hash->notrace_hash = EMPTY_HASH; } EXPORT_SYMBOL_GPL(ftrace_free_filter); @@ -3443,6 +3445,7 @@ static int add_next_hash(struct ftrace_hash **filter_hash, struct ftrace_hash ** size_bits); if (ret < 0) { free_ftrace_hash(*filter_hash); + *filter_hash = EMPTY_HASH; return ret; } } @@ -3472,6 +3475,7 @@ static int add_next_hash(struct ftrace_hash **filter_hash, struct ftrace_hash ** subops_hash->notrace_hash); if (ret < 0) { free_ftrace_hash(*notrace_hash); + *notrace_hash = EMPTY_HASH; return ret; } } From c45c585dde535e5ae2c363594bde3e05ce94a296 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 17 Apr 2025 13:59:39 -0400 Subject: [PATCH 3/7] ftrace: Free ftrace hashes after they are replaced in the subops code The subops processing creates new hashes when adding and removing subops. There were some places that the old hashes that were replaced were not freed and this caused some memory leaks. Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20250417135939.245b128d@gandalf.local.home Fixes: 0ae6b8ce200d ("ftrace: Fix accounting of subop hashes") Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index d0e4a902bb40..41dcfcf8b40a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3609,6 +3609,9 @@ static int rebuild_hashes(struct ftrace_hash **filter_hash, struct ftrace_hash * } } + free_ftrace_hash(temp_hash.filter_hash); + free_ftrace_hash(temp_hash.notrace_hash); + temp_hash.filter_hash = *filter_hash; temp_hash.notrace_hash = *notrace_hash; } @@ -3703,8 +3706,11 @@ static int ftrace_hash_move_and_update_subops(struct ftrace_ops *subops, } ret = rebuild_hashes(&filter_hash, ¬race_hash, ops); - if (!ret) + if (!ret) { ret = ftrace_update_ops(ops, filter_hash, notrace_hash); + free_ftrace_hash(filter_hash); + free_ftrace_hash(notrace_hash); + } if (ret) { /* Put back the original hash */ From 92f1d3b40179b15630d72e2c6e4e25a899b67ba9 Mon Sep 17 00:00:00 2001 From: Menglong Dong Date: Sun, 13 Apr 2025 09:44:44 +0800 Subject: [PATCH 4/7] ftrace: fix incorrect hash size in register_ftrace_direct() The maximum of the ftrace hash bits is made fls(32) in register_ftrace_direct(), which seems illogical. So, we fix it by making the max hash bits FTRACE_HASH_MAX_BITS instead. Link: https://lore.kernel.org/20250413014444.36724-1-dongml2@chinatelecom.cn Fixes: d05cb470663a ("ftrace: Fix modification of direct_function hash while in use") Signed-off-by: Menglong Dong Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 41dcfcf8b40a..61130bb34d6c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5964,9 +5964,10 @@ int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) /* Make a copy hash to place the new and the old entries in */ size = hash->count + direct_functions->count; - if (size > 32) - size = 32; - new_hash = alloc_ftrace_hash(fls(size)); + size = fls(size); + if (size > FTRACE_HASH_MAX_BITS) + size = FTRACE_HASH_MAX_BITS; + new_hash = alloc_ftrace_hash(size); if (!new_hash) goto out_unlock; From 3b4e87e6a593d571183c414d81758624da01f2b9 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Sun, 13 Apr 2025 00:10:43 +0200 Subject: [PATCH 5/7] ftrace: Fix type of ftrace_graph_ent_entry.depth ftrace_graph_ent.depth is int, but ftrace_graph_ent_entry.depth is unsigned long. This confuses trace-cmd on 64-bit big-endian systems and makes it print a huge amount of spaces. Fix this by using unsigned int, which has a matching size, instead. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Sven Schnelle Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Alexander Gordeev Link: https://lore.kernel.org/20250412221847.17310-2-iii@linux.ibm.com Fixes: ff5c9c576e75 ("ftrace: Add support for function argument to graph tracer") Signed-off-by: Ilya Leoshkevich Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_entries.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h index ee40d4e6ad1c..4ef4df6623a8 100644 --- a/kernel/trace/trace_entries.h +++ b/kernel/trace/trace_entries.h @@ -80,11 +80,11 @@ FTRACE_ENTRY(funcgraph_entry, ftrace_graph_ent_entry, F_STRUCT( __field_struct( struct ftrace_graph_ent, graph_ent ) __field_packed( unsigned long, graph_ent, func ) - __field_packed( unsigned long, graph_ent, depth ) + __field_packed( unsigned int, graph_ent, depth ) __dynamic_array(unsigned long, args ) ), - F_printk("--> %ps (%lu)", (void *)__entry->func, __entry->depth) + F_printk("--> %ps (%u)", (void *)__entry->func, __entry->depth) ); #ifdef CONFIG_FUNCTION_GRAPH_RETADDR From a8c5b0ed89a3f2c81c6ae0b041394e6eea0e7024 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 17 Apr 2025 18:30:03 -0400 Subject: [PATCH 6/7] tracing: Fix filter string testing The filter string testing uses strncpy_from_kernel/user_nofault() to retrieve the string to test the filter against. The if() statement was incorrect as it considered 0 as a fault, when it is only negative that it faulted. Running the following commands: # cd /sys/kernel/tracing # echo "filename.ustring ~ \"/proc*\"" > events/syscalls/sys_enter_openat/filter # echo 1 > events/syscalls/sys_enter_openat/enable # ls /proc/$$/maps # cat trace Would produce nothing, but with the fix it will produce something like: ls-1192 [007] ..... 8169.828333: sys_openat(dfd: ffffffffffffff9c, filename: 7efc18359904, flags: 80000, mode: 0) Link: https://lore.kernel.org/all/CAEf4BzbVPQ=BjWztmEwBPRKHUwNfKBkS3kce-Rzka6zvbQeVpg@mail.gmail.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Andrew Morton Link: https://lore.kernel.org/20250417183003.505835fb@gandalf.local.home Fixes: 77360f9bbc7e5 ("tracing: Add test for user space strings when filtering on string pointers") Reported-by: Andrii Nakryiko Reported-by: Mykyta Yatsenko Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_events_filter.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 0993dfc1c5c1..2048560264bb 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -808,7 +808,7 @@ static __always_inline char *test_string(char *str) kstr = ubuf->buffer; /* For safety, do not trust the string pointer */ - if (!strncpy_from_kernel_nofault(kstr, str, USTRING_BUF_SIZE)) + if (strncpy_from_kernel_nofault(kstr, str, USTRING_BUF_SIZE) < 0) return NULL; return kstr; } @@ -827,7 +827,7 @@ static __always_inline char *test_ustring(char *str) /* user space address? */ ustr = (char __user *)str; - if (!strncpy_from_user_nofault(kstr, ustr, USTRING_BUF_SIZE)) + if (strncpy_from_user_nofault(kstr, ustr, USTRING_BUF_SIZE) < 0) return NULL; return kstr; From d481ee35247d2a01764667a25f6f512c292ba42d Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 18 Apr 2025 10:12:08 -0400 Subject: [PATCH 7/7] tracing: selftests: Add testing a user string to filters Running the following commands was broken: # cd /sys/kernel/tracing # echo "filename.ustring ~ \"/proc*\"" > events/syscalls/sys_enter_openat/filter # echo 1 > events/syscalls/sys_enter_openat/enable # ls /proc/$$/maps # cat trace And would produce nothing when it should have produced something like: ls-1192 [007] ..... 8169.828333: sys_openat(dfd: ffffffffffffff9c, filename: 7efc18359904, flags: 80000, mode: 0) Add a test to check this case so that it will be caught if it breaks again. Link: https://lore.kernel.org/linux-trace-kernel/20250417183003.505835fb@gandalf.local.home/ Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Shuah Khan Link: https://lore.kernel.org/20250418101208.38dc81f5@gandalf.local.home Signed-off-by: Steven Rostedt (Google) --- .../test.d/filter/event-filter-function.tc | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/tools/testing/selftests/ftrace/test.d/filter/event-filter-function.tc b/tools/testing/selftests/ftrace/test.d/filter/event-filter-function.tc index 118247b8dd84..c62165fabd0c 100644 --- a/tools/testing/selftests/ftrace/test.d/filter/event-filter-function.tc +++ b/tools/testing/selftests/ftrace/test.d/filter/event-filter-function.tc @@ -80,6 +80,26 @@ if [ $misscnt -gt 0 ]; then exit_fail fi +# Check strings too +if [ -f events/syscalls/sys_enter_openat/filter ]; then + DIRNAME=`basename $TMPDIR` + echo "filename.ustring ~ \"*$DIRNAME*\"" > events/syscalls/sys_enter_openat/filter + echo 1 > events/syscalls/sys_enter_openat/enable + echo 1 > tracing_on + ls /bin/sh + nocnt=`grep openat trace | wc -l` + ls $TMPDIR + echo 0 > tracing_on + hitcnt=`grep openat trace | wc -l`; + echo 0 > events/syscalls/sys_enter_openat/enable + if [ $nocnt -gt 0 ]; then + exit_fail + fi + if [ $hitcnt -eq 0 ]; then + exit_fail + fi +fi + reset_events_filter exit 0