user/sven/linux.git/kernel/trace/trace_probe.c, branch v6.6.62

tracing: probes: Fix to zero initialize a local variable

2024-11-01T00:58:34Z

commit 0add699ad068d26e5b1da9ff28b15461fc4005df upstream. Fix to initialize 'val' local variable with zero. Dan reported that Smatch static code checker reports an error that a local 'val' variable needs to be initialized. Actually, the 'val' is expected to be initialized by FETCH_OP_ARG in the same loop, but it is not obvious. So initialize it with zero. Link: https://lore.kernel.org/all/171092223833.237219.17304490075697026697.stgit@devnote2/ Reported-by: Dan Carpenter Closes: https://lore.kernel.org/all/b010488e-68aa-407c-add0-3e059254aaa0@moroto.mountain/ Fixes: 25f00e40ce79 ("tracing/probes: Support $argN in return probe (kprobe and fprobe)") Reviewed-by: Steven Rostedt (Google) Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman

tracing: Consider the NULL character when validating the event length

2024-11-01T00:58:28Z

[ Upstream commit 0b6e2e22cb23105fcb171ab92f0f7516c69c8471 ] strlen() returns a string length excluding the null byte. If the string length equals to the maximum buffer length, the buffer will have no space for the NULL terminating character. This commit checks this condition and returns failure for it. Link: https://lore.kernel.org/all/20241007144724.920954-1-leo.yan@arm.com/ Fixes: dec65d79fd26 ("tracing/probe: Check event name length correctly") Signed-off-by: Leo Yan Reviewed-by: Steven Rostedt (Google) Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Sasha Levin

tracing/probes: Support $argN in return probe (kprobe and fprobe)

2024-11-01T00:58:26Z

[ Upstream commit 25f00e40ce7953db197af3a59233711d154c9d80 ] Support accessing $argN in the return probe events. This will help users to record entry data in function return (exit) event for simplfing the function entry/exit information in one event, and record the result values (e.g. allocated object/initialized object) at function exit. For example, if we have a function `int init_foo(struct foo *obj, int param)` sometimes we want to check how `obj` is initialized. In such case, we can define a new return event like below; # echo 'r init_foo retval=$retval param=$arg2 field1=+0($arg1)' >> kprobe_events Thus it records the function parameter `param` and its result `obj->field1` (the dereference will be done in the function exit timing) value at once. This also support fprobe, BTF args and'$arg*'. So if CONFIG_DEBUG_INFO_BTF is enabled, we can trace both function parameters and the return value by following command. # echo 'f target_function%return $arg* $retval' >> dynamic_events Link: https://lore.kernel.org/all/170952365552.229804.224112990211602895.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) Stable-dep-of: 373b9338c972 ("uprobe: avoid out-of-bounds memory access of fetching args") Signed-off-by: Sasha Levin

tracing/probes: cleanup: Set trace_probe::nr_args at trace_probe_init

2024-11-01T00:58:26Z

[ Upstream commit 035ba76014c096316fa809a46ce0a1b9af1cde0d ] Instead of incrementing the trace_probe::nr_args, init it at trace_probe_init(). Without this change, there is no way to get the number of trace_probe arguments while parsing it. This is a cleanup, so the behavior is not changed. Link: https://lore.kernel.org/all/170952363585.229804.13060759900346411951.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) Stable-dep-of: 373b9338c972 ("uprobe: avoid out-of-bounds memory access of fetching args") Signed-off-by: Sasha Levin

tracing/probes: fix error check in parse_btf_field()

2024-06-12T09:12:51Z

[ Upstream commit e569eb34970281438e2b48a3ef11c87459fcfbcb ] btf_find_struct_member() might return NULL or an error via the ERR_PTR() macro. However, its caller in parse_btf_field() only checks for the NULL condition. Fix this by using IS_ERR() and returning the error up the stack. Link: https://lore.kernel.org/all/20240527094351.15687-1-clopez@suse.de/ Fixes: c440adfbe3025 ("tracing/probes: Support BTF based data structure field access") Signed-off-by: Carlos López Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Sasha Levin

tracing/probes: Fix to set arg size and fmt after setting type from BTF

2024-02-23T08:25:05Z

commit 9a571c1e275cedacd48c66a6bddd0c23f1dffdbf upstream. Since the BTF type setting updates probe_arg::type, the type size calculation and setting print-fmt should be done after that. Without this fix, the argument size and print-fmt can be wrong. Link: https://lore.kernel.org/all/170602218196.215583.6417859469540955777.stgit@devnote2/ Fixes: b576e09701c7 ("tracing/probes: Support function parameters if BTF is available") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman

tracing/probes: Fix to show a parse error for bad type for $comm

2024-02-23T08:25:05Z

commit 8c427cc2fa73684ea140999e121b7b6c1c717632 upstream. Fix to show a parse error for bad type (non-string) for $comm/$COMM and immediate-string. With this fix, error_log file shows appropriate error message as below. /sys/kernel/tracing # echo 'p vfs_read $comm:u32' >> kprobe_events sh: write error: Invalid argument /sys/kernel/tracing # echo 'p vfs_read \"hoge":u32' >> kprobe_events sh: write error: Invalid argument /sys/kernel/tracing # cat error_log [ 30.144183] trace_kprobe: error: $comm and immediate-string only accepts string type Command: p vfs_read $comm:u32 ^ [ 62.618500] trace_kprobe: error: $comm and immediate-string only accepts string type Command: p vfs_read \"hoge":u32 ^ Link: https://lore.kernel.org/all/170602215411.215583.2238016352271091852.stgit@devnote2/ Fixes: 3dd1f7f24f8c ("tracing: probeevent: Fix to make the type of $comm string") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman

tracing/probes: Add string type check with BTF

2023-08-23T00:41:13Z

Add a string type checking with BTF information if possible. This will check whether the given BTF argument (and field) is signed char array or pointer to signed char. If not, it reject the 'string' type. If it is pointer to signed char, it adds a dereference opration so that it can correctly fetch the string data from memory. # echo 'f getname_flags%return retval->name:string' >> dynamic_events # echo 't sched_switch next->comm:string' >> dynamic_events The above cases, 'struct filename::name' is 'char *' and 'struct task_struct::comm' is 'char []'. But in both case, user can specify ':string' to fetch the string data. Link: https://lore.kernel.org/all/169272159250.160970.1881112937198526188.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) Acked-by: Steven Rostedt (Google)

tracing/probes: Support BTF field access from $retval

2023-08-23T00:40:51Z

Support BTF argument on '$retval' for function return events including kretprobe and fprobe for accessing the return value. This also allows user to access its fields if the return value is a pointer of a data structure. E.g. # echo 'f getname_flags%return +0($retval->name):string' \ > dynamic_events # echo 1 > events/fprobes/getname_flags__exit/enable # ls > /dev/null # head -n 40 trace | tail ls-87 [000] ...1. 8067.616101: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./function_profile_enabled" ls-87 [000] ...1. 8067.616108: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./trace_stat" ls-87 [000] ...1. 8067.616115: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_graph_notrace" ls-87 [000] ...1. 8067.616122: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_graph_function" ls-87 [000] ...1. 8067.616129: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_ftrace_notrace" ls-87 [000] ...1. 8067.616135: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_ftrace_filter" ls-87 [000] ...1. 8067.616143: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./touched_functions" ls-87 [000] ...1. 8067.616237: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./enabled_functions" ls-87 [000] ...1. 8067.616245: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./available_filter_functions" ls-87 [000] ...1. 8067.616253: getname_flags__exit: (vfs_fstatat+0x3c/0x70 <- getname_flags) arg1="./set_ftrace_notrace_pid" Link: https://lore.kernel.org/all/169272158234.160970.2446691104240645205.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) Acked-by: Steven Rostedt (Google)

tracing/probes: Support BTF based data structure field access

2023-08-23T00:40:28Z

Using BTF to access the fields of a data structure. You can use this for accessing the field with '->' or '.' operation with BTF argument. # echo 't sched_switch next=next->pid vruntime=next->se.vruntime' \ > dynamic_events # echo 1 > events/tracepoints/sched_switch/enable # head -n 40 trace | tail -0 [000] d..3. 272.565382: sched_switch: (__probestub_sched_switch+0x4/0x10) next=26 vruntime=956533179 kcompactd0-26 [000] d..3. 272.565406: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0 -0 [000] d..3. 273.069441: sched_switch: (__probestub_sched_switch+0x4/0x10) next=9 vruntime=956533179 kworker/0:1-9 [000] d..3. 273.069464: sched_switch: (__probestub_sched_switch+0x4/0x10) next=26 vruntime=956579181 kcompactd0-26 [000] d..3. 273.069480: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0 -0 [000] d..3. 273.141434: sched_switch: (__probestub_sched_switch+0x4/0x10) next=22 vruntime=956533179 kworker/u2:1-22 [000] d..3. 273.141461: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0 -0 [000] d..3. 273.480872: sched_switch: (__probestub_sched_switch+0x4/0x10) next=22 vruntime=956585857 kworker/u2:1-22 [000] d..3. 273.480905: sched_switch: (__probestub_sched_switch+0x4/0x10) next=70 vruntime=959533179 sh-70 [000] d..3. 273.481102: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0 Link: https://lore.kernel.org/all/169272157251.160970.9318175874130965571.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Alan Maguire Acked-by: Steven Rostedt (Google)