* [PATCH v2 2/3] tracing: Update futex syscall trace event to show more commands
2026-03-10 20:09 [PATCH v2 0/3] tracing: Read user data from futex system call trace event Steven Rostedt
@ 2026-03-10 20:09 ` Steven Rostedt
2026-03-12 5:34 ` Masami Hiramatsu
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2026-03-10 20:09 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Thomas Gleixner, Peter Zijlstra, Brian Geffon, John Stultz,
Ian Rogers, Suleiman Souhlal
From: Steven Rostedt <rostedt@goodmis.org>
Make the futex syscall trace event a little more smart. Have it read the
futex_op instruction to determine what else it can save and print. For the
appropriate options, it will read the utime (timespec) parameter and show
its output as well as the uaddr2.
futex_requeue_p-1154 [004] ..... 144.568339: sys_futex(uaddr: 0x5652b178d834 (0x482), FUTEX_UNLOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
futex_requeue_p-1162 [002] ..... 144.568696: sys_futex(uaddr: 0x7f763b7fece0 (2), FUTEX_WAIT|FUTEX_PRIVATE_FLAG, val: 2)
futex_requeue_p-1151 [000] ..... 144.568700: sys_futex(uaddr: 0x7f763b7fece0 (0), FUTEX_WAKE|FUTEX_PRIVATE_FLAG, val: 1)
futex_requeue_p-1162 [002] ..... 144.568705: sys_futex(uaddr: 0x7f763b7fece0 (0), FUTEX_WAKE|FUTEX_PRIVATE_FLAG, val: 1)
futex_requeue_p-1151 [000] ..... 144.568715: sys_futex(uaddr: 0x7f764369e990 (0x483), FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, val: 1155)
futex_requeue_p-1155 [005] ..... 144.569420: sys_futex(uaddr: 0x5652b178d838 (0), FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG, val: 0, timespec: 0x7ffdacfba500 (143.890024054), uaddr2: 0x5652b178d834 (0), val3: 0)
futex_requeue_p-1155 [005] ..... 144.569454: sys_futex(uaddr: 0x5652b178d834 (0), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v1: https://lore.kernel.org/all/20260303214942.587739736@kernel.org/
- Updated to have the print processing in kernel/futex/syscall.c
include/linux/futex.h | 35 ++++++++-
kernel/futex/syscalls.c | 48 ++++++-------
kernel/trace/trace_syscalls.c | 129 +++++++++++++++++++++++++++++-----
3 files changed, 164 insertions(+), 48 deletions(-)
diff --git a/include/linux/futex.h b/include/linux/futex.h
index 9fc47aa01a8b..976fa257ab5c 100644
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -82,8 +82,35 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
u32 __user *uaddr2, u32 val2, u32 val3);
int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4);
+static __always_inline bool futex_cmd_has_timeout(u32 cmd)
+{
+ switch (cmd) {
+ case FUTEX_WAIT:
+ case FUTEX_LOCK_PI:
+ case FUTEX_LOCK_PI2:
+ case FUTEX_WAIT_BITSET:
+ case FUTEX_WAIT_REQUEUE_PI:
+ return true;
+ }
+ return false;
+}
+
+static __always_inline bool futex_cmd_has_addr2(u32 cmd)
+{
+ switch (cmd) {
+ case FUTEX_REQUEUE:
+ case FUTEX_CMP_REQUEUE:
+ case FUTEX_WAKE_OP:
+ case FUTEX_WAIT_REQUEUE_PI:
+ return true;
+ }
+ return false;
+}
+
#ifdef CONFIG_FTRACE_SYSCALLS
-void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u32 *ptr);
+void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args,
+ u32 *ptr1, u32 *ptr2, unsigned long *ts1,
+ unsigned long *ts2);
#endif
#ifdef CONFIG_FUTEX_PRIVATE_HASH
@@ -119,7 +146,11 @@ static inline int futex_hash_allocate_default(void)
static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
static inline int futex_mm_init(struct mm_struct *mm) { return 0; }
static inline void futex_print_syscall(struct seq_buf *s, int nr_args,
- unsigned long *args, u32 *ptr) { }
+ unsigned long *args, u32 *ptr1,
+ u32 *ptr2, unsigned long *ts1,
+ unsigned long *ts2) { }
+static __always_inline bool futex_cmd_has_timeout(u32 cmd) { return false; }
+static __always_inline bool futex_cmd_has_addr2(u32 cmd) { return false; }
#endif
#endif
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
index a1cd512aa502..a46706d6bc6c 100644
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -158,31 +158,6 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
return -ENOSYS;
}
-static __always_inline bool futex_cmd_has_timeout(u32 cmd)
-{
- switch (cmd) {
- case FUTEX_WAIT:
- case FUTEX_LOCK_PI:
- case FUTEX_LOCK_PI2:
- case FUTEX_WAIT_BITSET:
- case FUTEX_WAIT_REQUEUE_PI:
- return true;
- }
- return false;
-}
-
-static __always_inline bool futex_cmd_has_addr2(u32 cmd)
-{
- switch (cmd) {
- case FUTEX_REQUEUE:
- case FUTEX_CMP_REQUEUE:
- case FUTEX_WAKE_OP:
- case FUTEX_WAIT_REQUEUE_PI:
- return true;
- }
- return false;
-}
-
static __always_inline int
futex_init_timeout(u32 cmd, u32 op, struct timespec64 *ts, ktime_t *t)
{
@@ -229,7 +204,9 @@ static const char * __futex_cmds[] =
"FUTEX_LOCK_PI2",
};
-void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u32 *ptr)
+void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args,
+ u32 *ptr1, u32 *ptr2, unsigned long *ts1,
+ unsigned long *ts2)
{
unsigned int op, cmd;
bool done = false;
@@ -242,8 +219,8 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
switch (i) {
case 0:
seq_buf_printf(s, "uaddr: 0x%lx", args[i]);
- if (ptr) {
- u32 val = *ptr;
+ if (ptr1) {
+ u32 val = *ptr1;
if (val < 10)
seq_buf_printf(s, " (%u)", val);
else
@@ -279,6 +256,15 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
continue;
seq_buf_printf(s, ", timespec: 0x%lx", args[i]);
+
+ if (!ts1 || !ts2)
+ continue;
+
+ if (!*ts1 && !*ts2) {
+ seq_buf_puts(s, " (0)");
+ continue;
+ }
+ seq_buf_printf(s, " (%lu.%09lu)", *ts1, *ts2);
continue;
case 4:
if (!futex_cmd_has_addr2(cmd)) {
@@ -286,6 +272,12 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
continue;
}
seq_buf_printf(s, ", uaddr2: 0x%lx", args[i]);
+
+ if (!ptr2)
+ continue;
+
+ seq_buf_printf(s, " (%x)", *ptr2);
+
continue;
case 5:
seq_buf_printf(s, ", val3: %lu", args[i]);
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 8cb3af569157..de1fa97547a3 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -239,21 +239,35 @@ sys_enter_openat_print(struct syscall_trace_enter *trace, struct syscall_metadat
return trace_handle_return(s);
}
+struct futex_data {
+ u32 val1;
+ u32 val2;
+ unsigned long ts1;
+ unsigned long ts2;
+};
+
static enum print_line_t
sys_enter_futex_print(struct syscall_trace_enter *trace, struct syscall_metadata *entry,
struct trace_seq *s, struct trace_event *event, int ent_size)
{
+ struct futex_data *data;
void *end = (void *)trace + ent_size;
- void *ptr;
+ unsigned long *ts1 = NULL, *ts2 = NULL;
+ u32 *ptr1 = NULL, *ptr2 = NULL;
/* Set ptr to the user space copied area */
- ptr = (void *)trace->args + sizeof(unsigned long) * entry->nb_args;
- if (ptr + 4 > end)
- ptr = NULL;
+ data = (void *)trace->args + sizeof(unsigned long) * entry->nb_args;
+ if ((void *)data + sizeof(*data) <= end) {
+ ptr1 = &data->val1;
+ ptr2 = &data->val2;
+ ts1 = &data->ts1;
+ ts2 = &data->ts2;
+ }
trace_seq_printf(s, "%s(", entry->name);
- futex_print_syscall(&s->seq, entry->nb_args, trace->args, ptr);
+ futex_print_syscall(&s->seq, entry->nb_args, trace->args, ptr1, ptr2,
+ ts1, ts2);
trace_seq_puts(s, ")\n");
@@ -472,9 +486,9 @@ sys_enter_futex_print_fmt(struct syscall_metadata *entry, char *buf, int len)
pos += snprintf(buf + pos, LEN_OR_ZERO,
"\"uaddr: 0x%%lx (0x%%lx) cmd=%%s%%s%%s");
pos += snprintf(buf + pos, LEN_OR_ZERO,
- " val: 0x%%x timeout/val2: 0x%%llx");
+ " val: 0x%%x timeout/val2: 0x%%llx (%%lu.%%lu)");
pos += snprintf(buf + pos, LEN_OR_ZERO,
- " uaddr2: 0x%%lx val3: 0x%%x\", ");
+ " uaddr2: 0x%%lx (0x%%lx) val3: 0x%%x\", ");
pos += snprintf(buf + pos, LEN_OR_ZERO,
" REC->uaddr,");
@@ -520,10 +534,12 @@ sys_enter_futex_print_fmt(struct syscall_metadata *entry, char *buf, int len)
FUTEX_CLOCK_REALTIME);
pos += snprintf(buf + pos, LEN_OR_ZERO,
- " REC->val, REC->utime,");
+ " REC->val, REC->utime, REC->__ts1, REC->__ts2,");
pos += snprintf(buf + pos, LEN_OR_ZERO,
- " REC->uaddr, REC->val3");
+ " REC->uaddr,");
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " REC->__value2, REC->val3");
return pos;
}
@@ -626,7 +642,39 @@ static int __init futex_fields(struct trace_event_call *call, int offset)
ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
FILTER_OTHER);
if (ret)
- kfree(arg);
+ goto free;
+ offset += sizeof(int);
+
+ arg = kstrdup("__value2", GFP_KERNEL);
+ if (WARN_ON_ONCE(!arg))
+ return -ENOMEM;
+ ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
+ FILTER_OTHER);
+ if (ret)
+ goto free;
+ offset += sizeof(int);
+
+ arg = kstrdup("__ts1", GFP_KERNEL);
+ if (WARN_ON_ONCE(!arg))
+ return -ENOMEM;
+ ret = trace_define_field(call, "unsigned long", arg, offset,
+ sizeof(unsigned long), 0, FILTER_OTHER);
+ if (ret)
+ goto free;
+ offset += sizeof(long);
+
+ arg = kstrdup("__ts2", GFP_KERNEL);
+ if (WARN_ON_ONCE(!arg))
+ return -ENOMEM;
+ ret = trace_define_field(call, "unsigned long", arg, offset,
+ sizeof(unsigned long), 0, FILTER_OTHER);
+ if (ret)
+ goto free;
+
+ return 0;
+
+free:
+ kfree(arg);
return ret;
}
@@ -799,11 +847,51 @@ static int syscall_copy_user_array(char *buf, const char __user *ptr,
return 0;
}
+struct tp_futex_data {
+ u32 cmd;
+ const u32 __user *val1;
+ const u32 __user *val2;
+ void __user *timeout;
+};
+
+static int syscall_copy_futex(char *buf, const char __user *ptr,
+ size_t size, void *data)
+{
+ struct tp_futex_data *tp_data = data;
+ struct futex_data *fdata = (void *)buf;
+ int cmd = tp_data->cmd & FUTEX_CMD_MASK;
+ int ret;
+
+ memset(fdata, 0, sizeof(*fdata));
+
+ if (tp_data->val1) {
+ ret = __copy_from_user(&fdata->val1, tp_data->val1, 4);
+ if (ret)
+ return -1;
+ }
+
+ if (tp_data->val2 && futex_cmd_has_addr2(cmd)) {
+ ret = __copy_from_user(&fdata->val2, tp_data->val2, 4);
+ if (ret)
+ return -1;
+ }
+
+ if (tp_data->timeout && futex_cmd_has_timeout(cmd)) {
+ /* Copies both ts1 and ts2 */
+ ret = __copy_from_user(&fdata->ts1, tp_data->timeout,
+ sizeof(long) * 2);
+ if (ret)
+ return -1;
+ }
+
+ return 0;
+}
+
static int
syscall_get_futex(unsigned long *args, char **buffer, int *size, int buf_size)
{
struct syscall_user_buffer *sbuf;
- const char __user *ptr;
+ struct tp_futex_data tp_data;
char *buf;
/* buf_size of zero means user doesn't want user space read */
@@ -815,14 +903,18 @@ syscall_get_futex(unsigned long *args, char **buffer, int *size, int buf_size)
if (!sbuf)
return -1;
- ptr = (char __user *)args[0];
+ tp_data.cmd = args[1];
+ tp_data.val1 = (u32 __user *)args[0];
+ tp_data.val2 = (u32 __user *)args[4];
+ tp_data.timeout = (u64 __user *)args[3];
- *buffer = trace_user_fault_read(&sbuf->buf, ptr, 4, NULL, NULL);
+ *buffer = trace_user_fault_read(&sbuf->buf, NULL, 0,
+ syscall_copy_futex, &tp_data);
if (!*buffer)
return -1;
- /* Add room for the value */
- *size += 4;
+ /* Add room for values */
+ *size += sizeof(struct futex_data);
buf = *buffer;
@@ -833,12 +925,13 @@ static void syscall_put_futex(struct syscall_metadata *sys_data,
struct syscall_trace_enter *entry,
char *buffer)
{
- u32 *ptr;
+ struct futex_data *fdata = (void *)buffer;
+ struct futex_data *data;
/* Place the futex key into the storage */
- ptr = (void *)entry->args + sizeof(unsigned long) * sys_data->nb_args;
+ data = (void *)entry->args + sizeof(unsigned long) * sys_data->nb_args;
- *ptr = *(u32 *)buffer;
+ *data = *fdata;
}
static char *sys_fault_user(unsigned int buf_size,
--
2.51.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2 2/3] tracing: Update futex syscall trace event to show more commands
2026-03-10 20:09 ` [PATCH v2 2/3] tracing: Update futex syscall trace event to show more commands Steven Rostedt
@ 2026-03-12 5:34 ` Masami Hiramatsu
0 siblings, 0 replies; 3+ messages in thread
From: Masami Hiramatsu @ 2026-03-12 5:34 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, linux-trace-kernel, Masami Hiramatsu, Mark Rutland,
Mathieu Desnoyers, Andrew Morton, Thomas Gleixner, Peter Zijlstra,
Brian Geffon, John Stultz, Ian Rogers, Suleiman Souhlal
On Tue, 10 Mar 2026 16:09:56 -0400
Steven Rostedt <rostedt@kernel.org> wrote:
> From: Steven Rostedt <rostedt@goodmis.org>
>
> Make the futex syscall trace event a little more smart. Have it read the
> futex_op instruction to determine what else it can save and print. For the
> appropriate options, it will read the utime (timespec) parameter and show
> its output as well as the uaddr2.
>
> futex_requeue_p-1154 [004] ..... 144.568339: sys_futex(uaddr: 0x5652b178d834 (0x482), FUTEX_UNLOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
> futex_requeue_p-1162 [002] ..... 144.568696: sys_futex(uaddr: 0x7f763b7fece0 (2), FUTEX_WAIT|FUTEX_PRIVATE_FLAG, val: 2)
> futex_requeue_p-1151 [000] ..... 144.568700: sys_futex(uaddr: 0x7f763b7fece0 (0), FUTEX_WAKE|FUTEX_PRIVATE_FLAG, val: 1)
> futex_requeue_p-1162 [002] ..... 144.568705: sys_futex(uaddr: 0x7f763b7fece0 (0), FUTEX_WAKE|FUTEX_PRIVATE_FLAG, val: 1)
> futex_requeue_p-1151 [000] ..... 144.568715: sys_futex(uaddr: 0x7f764369e990 (0x483), FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, val: 1155)
> futex_requeue_p-1155 [005] ..... 144.569420: sys_futex(uaddr: 0x5652b178d838 (0), FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG, val: 0, timespec: 0x7ffdacfba500 (143.890024054), uaddr2: 0x5652b178d834 (0), val3: 0)
> futex_requeue_p-1155 [005] ..... 144.569454: sys_futex(uaddr: 0x5652b178d834 (0), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This looks good to me.
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Thanks,
> ---
> Changes since v1: https://lore.kernel.org/all/20260303214942.587739736@kernel.org/
>
> - Updated to have the print processing in kernel/futex/syscall.c
>
> include/linux/futex.h | 35 ++++++++-
> kernel/futex/syscalls.c | 48 ++++++-------
> kernel/trace/trace_syscalls.c | 129 +++++++++++++++++++++++++++++-----
> 3 files changed, 164 insertions(+), 48 deletions(-)
>
> diff --git a/include/linux/futex.h b/include/linux/futex.h
> index 9fc47aa01a8b..976fa257ab5c 100644
> --- a/include/linux/futex.h
> +++ b/include/linux/futex.h
> @@ -82,8 +82,35 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
> u32 __user *uaddr2, u32 val2, u32 val3);
> int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4);
>
> +static __always_inline bool futex_cmd_has_timeout(u32 cmd)
> +{
> + switch (cmd) {
> + case FUTEX_WAIT:
> + case FUTEX_LOCK_PI:
> + case FUTEX_LOCK_PI2:
> + case FUTEX_WAIT_BITSET:
> + case FUTEX_WAIT_REQUEUE_PI:
> + return true;
> + }
> + return false;
> +}
> +
> +static __always_inline bool futex_cmd_has_addr2(u32 cmd)
> +{
> + switch (cmd) {
> + case FUTEX_REQUEUE:
> + case FUTEX_CMP_REQUEUE:
> + case FUTEX_WAKE_OP:
> + case FUTEX_WAIT_REQUEUE_PI:
> + return true;
> + }
> + return false;
> +}
> +
> #ifdef CONFIG_FTRACE_SYSCALLS
> -void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u32 *ptr);
> +void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args,
> + u32 *ptr1, u32 *ptr2, unsigned long *ts1,
> + unsigned long *ts2);
> #endif
>
> #ifdef CONFIG_FUTEX_PRIVATE_HASH
> @@ -119,7 +146,11 @@ static inline int futex_hash_allocate_default(void)
> static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
> static inline int futex_mm_init(struct mm_struct *mm) { return 0; }
> static inline void futex_print_syscall(struct seq_buf *s, int nr_args,
> - unsigned long *args, u32 *ptr) { }
> + unsigned long *args, u32 *ptr1,
> + u32 *ptr2, unsigned long *ts1,
> + unsigned long *ts2) { }
> +static __always_inline bool futex_cmd_has_timeout(u32 cmd) { return false; }
> +static __always_inline bool futex_cmd_has_addr2(u32 cmd) { return false; }
> #endif
>
> #endif
> diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
> index a1cd512aa502..a46706d6bc6c 100644
> --- a/kernel/futex/syscalls.c
> +++ b/kernel/futex/syscalls.c
> @@ -158,31 +158,6 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
> return -ENOSYS;
> }
>
> -static __always_inline bool futex_cmd_has_timeout(u32 cmd)
> -{
> - switch (cmd) {
> - case FUTEX_WAIT:
> - case FUTEX_LOCK_PI:
> - case FUTEX_LOCK_PI2:
> - case FUTEX_WAIT_BITSET:
> - case FUTEX_WAIT_REQUEUE_PI:
> - return true;
> - }
> - return false;
> -}
> -
> -static __always_inline bool futex_cmd_has_addr2(u32 cmd)
> -{
> - switch (cmd) {
> - case FUTEX_REQUEUE:
> - case FUTEX_CMP_REQUEUE:
> - case FUTEX_WAKE_OP:
> - case FUTEX_WAIT_REQUEUE_PI:
> - return true;
> - }
> - return false;
> -}
> -
> static __always_inline int
> futex_init_timeout(u32 cmd, u32 op, struct timespec64 *ts, ktime_t *t)
> {
> @@ -229,7 +204,9 @@ static const char * __futex_cmds[] =
> "FUTEX_LOCK_PI2",
> };
>
> -void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u32 *ptr)
> +void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args,
> + u32 *ptr1, u32 *ptr2, unsigned long *ts1,
> + unsigned long *ts2)
> {
> unsigned int op, cmd;
> bool done = false;
> @@ -242,8 +219,8 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
> switch (i) {
> case 0:
> seq_buf_printf(s, "uaddr: 0x%lx", args[i]);
> - if (ptr) {
> - u32 val = *ptr;
> + if (ptr1) {
> + u32 val = *ptr1;
> if (val < 10)
> seq_buf_printf(s, " (%u)", val);
> else
> @@ -279,6 +256,15 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
> continue;
>
> seq_buf_printf(s, ", timespec: 0x%lx", args[i]);
> +
> + if (!ts1 || !ts2)
> + continue;
> +
> + if (!*ts1 && !*ts2) {
> + seq_buf_puts(s, " (0)");
> + continue;
> + }
> + seq_buf_printf(s, " (%lu.%09lu)", *ts1, *ts2);
> continue;
> case 4:
> if (!futex_cmd_has_addr2(cmd)) {
> @@ -286,6 +272,12 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
> continue;
> }
> seq_buf_printf(s, ", uaddr2: 0x%lx", args[i]);
> +
> + if (!ptr2)
> + continue;
> +
> + seq_buf_printf(s, " (%x)", *ptr2);
> +
> continue;
> case 5:
> seq_buf_printf(s, ", val3: %lu", args[i]);
> diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
> index 8cb3af569157..de1fa97547a3 100644
> --- a/kernel/trace/trace_syscalls.c
> +++ b/kernel/trace/trace_syscalls.c
> @@ -239,21 +239,35 @@ sys_enter_openat_print(struct syscall_trace_enter *trace, struct syscall_metadat
> return trace_handle_return(s);
> }
>
> +struct futex_data {
> + u32 val1;
> + u32 val2;
> + unsigned long ts1;
> + unsigned long ts2;
> +};
> +
> static enum print_line_t
> sys_enter_futex_print(struct syscall_trace_enter *trace, struct syscall_metadata *entry,
> struct trace_seq *s, struct trace_event *event, int ent_size)
> {
> + struct futex_data *data;
> void *end = (void *)trace + ent_size;
> - void *ptr;
> + unsigned long *ts1 = NULL, *ts2 = NULL;
> + u32 *ptr1 = NULL, *ptr2 = NULL;
>
> /* Set ptr to the user space copied area */
> - ptr = (void *)trace->args + sizeof(unsigned long) * entry->nb_args;
> - if (ptr + 4 > end)
> - ptr = NULL;
> + data = (void *)trace->args + sizeof(unsigned long) * entry->nb_args;
> + if ((void *)data + sizeof(*data) <= end) {
> + ptr1 = &data->val1;
> + ptr2 = &data->val2;
> + ts1 = &data->ts1;
> + ts2 = &data->ts2;
> + }
>
> trace_seq_printf(s, "%s(", entry->name);
>
> - futex_print_syscall(&s->seq, entry->nb_args, trace->args, ptr);
> + futex_print_syscall(&s->seq, entry->nb_args, trace->args, ptr1, ptr2,
> + ts1, ts2);
>
> trace_seq_puts(s, ")\n");
>
> @@ -472,9 +486,9 @@ sys_enter_futex_print_fmt(struct syscall_metadata *entry, char *buf, int len)
> pos += snprintf(buf + pos, LEN_OR_ZERO,
> "\"uaddr: 0x%%lx (0x%%lx) cmd=%%s%%s%%s");
> pos += snprintf(buf + pos, LEN_OR_ZERO,
> - " val: 0x%%x timeout/val2: 0x%%llx");
> + " val: 0x%%x timeout/val2: 0x%%llx (%%lu.%%lu)");
> pos += snprintf(buf + pos, LEN_OR_ZERO,
> - " uaddr2: 0x%%lx val3: 0x%%x\", ");
> + " uaddr2: 0x%%lx (0x%%lx) val3: 0x%%x\", ");
>
> pos += snprintf(buf + pos, LEN_OR_ZERO,
> " REC->uaddr,");
> @@ -520,10 +534,12 @@ sys_enter_futex_print_fmt(struct syscall_metadata *entry, char *buf, int len)
> FUTEX_CLOCK_REALTIME);
>
> pos += snprintf(buf + pos, LEN_OR_ZERO,
> - " REC->val, REC->utime,");
> + " REC->val, REC->utime, REC->__ts1, REC->__ts2,");
>
> pos += snprintf(buf + pos, LEN_OR_ZERO,
> - " REC->uaddr, REC->val3");
> + " REC->uaddr,");
> + pos += snprintf(buf + pos, LEN_OR_ZERO,
> + " REC->__value2, REC->val3");
> return pos;
> }
>
> @@ -626,7 +642,39 @@ static int __init futex_fields(struct trace_event_call *call, int offset)
> ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
> FILTER_OTHER);
> if (ret)
> - kfree(arg);
> + goto free;
> + offset += sizeof(int);
> +
> + arg = kstrdup("__value2", GFP_KERNEL);
> + if (WARN_ON_ONCE(!arg))
> + return -ENOMEM;
> + ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
> + FILTER_OTHER);
> + if (ret)
> + goto free;
> + offset += sizeof(int);
> +
> + arg = kstrdup("__ts1", GFP_KERNEL);
> + if (WARN_ON_ONCE(!arg))
> + return -ENOMEM;
> + ret = trace_define_field(call, "unsigned long", arg, offset,
> + sizeof(unsigned long), 0, FILTER_OTHER);
> + if (ret)
> + goto free;
> + offset += sizeof(long);
> +
> + arg = kstrdup("__ts2", GFP_KERNEL);
> + if (WARN_ON_ONCE(!arg))
> + return -ENOMEM;
> + ret = trace_define_field(call, "unsigned long", arg, offset,
> + sizeof(unsigned long), 0, FILTER_OTHER);
> + if (ret)
> + goto free;
> +
> + return 0;
> +
> +free:
> + kfree(arg);
> return ret;
> }
>
> @@ -799,11 +847,51 @@ static int syscall_copy_user_array(char *buf, const char __user *ptr,
> return 0;
> }
>
> +struct tp_futex_data {
> + u32 cmd;
> + const u32 __user *val1;
> + const u32 __user *val2;
> + void __user *timeout;
> +};
> +
> +static int syscall_copy_futex(char *buf, const char __user *ptr,
> + size_t size, void *data)
> +{
> + struct tp_futex_data *tp_data = data;
> + struct futex_data *fdata = (void *)buf;
> + int cmd = tp_data->cmd & FUTEX_CMD_MASK;
> + int ret;
> +
> + memset(fdata, 0, sizeof(*fdata));
> +
> + if (tp_data->val1) {
> + ret = __copy_from_user(&fdata->val1, tp_data->val1, 4);
> + if (ret)
> + return -1;
> + }
> +
> + if (tp_data->val2 && futex_cmd_has_addr2(cmd)) {
> + ret = __copy_from_user(&fdata->val2, tp_data->val2, 4);
> + if (ret)
> + return -1;
> + }
> +
> + if (tp_data->timeout && futex_cmd_has_timeout(cmd)) {
> + /* Copies both ts1 and ts2 */
> + ret = __copy_from_user(&fdata->ts1, tp_data->timeout,
> + sizeof(long) * 2);
> + if (ret)
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> static int
> syscall_get_futex(unsigned long *args, char **buffer, int *size, int buf_size)
> {
> struct syscall_user_buffer *sbuf;
> - const char __user *ptr;
> + struct tp_futex_data tp_data;
> char *buf;
>
> /* buf_size of zero means user doesn't want user space read */
> @@ -815,14 +903,18 @@ syscall_get_futex(unsigned long *args, char **buffer, int *size, int buf_size)
> if (!sbuf)
> return -1;
>
> - ptr = (char __user *)args[0];
> + tp_data.cmd = args[1];
> + tp_data.val1 = (u32 __user *)args[0];
> + tp_data.val2 = (u32 __user *)args[4];
> + tp_data.timeout = (u64 __user *)args[3];
>
> - *buffer = trace_user_fault_read(&sbuf->buf, ptr, 4, NULL, NULL);
> + *buffer = trace_user_fault_read(&sbuf->buf, NULL, 0,
> + syscall_copy_futex, &tp_data);
> if (!*buffer)
> return -1;
>
> - /* Add room for the value */
> - *size += 4;
> + /* Add room for values */
> + *size += sizeof(struct futex_data);
>
> buf = *buffer;
>
> @@ -833,12 +925,13 @@ static void syscall_put_futex(struct syscall_metadata *sys_data,
> struct syscall_trace_enter *entry,
> char *buffer)
> {
> - u32 *ptr;
> + struct futex_data *fdata = (void *)buffer;
> + struct futex_data *data;
>
> /* Place the futex key into the storage */
> - ptr = (void *)entry->args + sizeof(unsigned long) * sys_data->nb_args;
> + data = (void *)entry->args + sizeof(unsigned long) * sys_data->nb_args;
>
> - *ptr = *(u32 *)buffer;
> + *data = *fdata;
> }
>
> static char *sys_fault_user(unsigned int buf_size,
> --
> 2.51.0
>
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2 2/3] tracing: Update futex syscall trace event to show more commands
@ 2026-03-12 22:49 kernel test robot
0 siblings, 0 replies; 3+ messages in thread
From: kernel test robot @ 2026-03-12 22:49 UTC (permalink / raw)
To: oe-kbuild; +Cc: lkp, Dan Carpenter
BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20260310201036.713629966@kernel.org>
References: <20260310201036.713629966@kernel.org>
TO: Steven Rostedt <rostedt@goodmis.org>
TO: linux-kernel@vger.kernel.org
TO: linux-trace-kernel@vger.kernel.org
CC: Masami Hiramatsu <mhiramat@kernel.org>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linux Memory Management List <linux-mm@kvack.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Brian Geffon <bgeffon@google.com>
CC: John Stultz <jstultz@google.com>
CC: Ian Rogers <irogers@google.com>
CC: Suleiman Souhlal <suleiman@google.com>
Hi Steven,
kernel test robot noticed the following build warnings:
[auto build test WARNING on tip/locking/core]
[also build test WARNING on trace/for-next akpm-mm/mm-everything linus/master v7.0-rc3 next-20260311]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Steven-Rostedt/tracing-Have-futex-syscall-trace-event-show-specific-user-data/20260311-041422
base: tip/locking/core
patch link: https://lore.kernel.org/r/20260310201036.713629966%40kernel.org
patch subject: [PATCH v2 2/3] tracing: Update futex syscall trace event to show more commands
:::::: branch date: 2 days ago
:::::: commit date: 2 days ago
config: i386-randconfig-141-20260311 (https://download.01.org/0day-ci/archive/20260313/202603130608.WKdib8MH-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
smatch: v0.5.0-9004-gb810ac53
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202603130608.WKdib8MH-lkp@intel.com/
smatch warnings:
kernel/trace/trace_syscalls.c:650 futex_fields() warn: missing unwind goto?
vim +650 kernel/trace/trace_syscalls.c
50307a45f8515f Lai Jiangshan 2009-12-15 633
15901aaefa1313 Steven Rostedt 2026-03-10 634 static int __init futex_fields(struct trace_event_call *call, int offset)
15901aaefa1313 Steven Rostedt 2026-03-10 635 {
15901aaefa1313 Steven Rostedt 2026-03-10 636 char *arg;
15901aaefa1313 Steven Rostedt 2026-03-10 637 int ret;
15901aaefa1313 Steven Rostedt 2026-03-10 638
15901aaefa1313 Steven Rostedt 2026-03-10 639 arg = kstrdup("__value", GFP_KERNEL);
15901aaefa1313 Steven Rostedt 2026-03-10 640 if (WARN_ON_ONCE(!arg))
15901aaefa1313 Steven Rostedt 2026-03-10 641 return -ENOMEM;
15901aaefa1313 Steven Rostedt 2026-03-10 642 ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
15901aaefa1313 Steven Rostedt 2026-03-10 643 FILTER_OTHER);
15901aaefa1313 Steven Rostedt 2026-03-10 644 if (ret)
f3ff4ed51edb59 Steven Rostedt 2026-03-10 645 goto free;
f3ff4ed51edb59 Steven Rostedt 2026-03-10 646 offset += sizeof(int);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 647
f3ff4ed51edb59 Steven Rostedt 2026-03-10 648 arg = kstrdup("__value2", GFP_KERNEL);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 649 if (WARN_ON_ONCE(!arg))
f3ff4ed51edb59 Steven Rostedt 2026-03-10 @650 return -ENOMEM;
f3ff4ed51edb59 Steven Rostedt 2026-03-10 651 ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
f3ff4ed51edb59 Steven Rostedt 2026-03-10 652 FILTER_OTHER);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 653 if (ret)
f3ff4ed51edb59 Steven Rostedt 2026-03-10 654 goto free;
f3ff4ed51edb59 Steven Rostedt 2026-03-10 655 offset += sizeof(int);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 656
f3ff4ed51edb59 Steven Rostedt 2026-03-10 657 arg = kstrdup("__ts1", GFP_KERNEL);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 658 if (WARN_ON_ONCE(!arg))
f3ff4ed51edb59 Steven Rostedt 2026-03-10 659 return -ENOMEM;
f3ff4ed51edb59 Steven Rostedt 2026-03-10 660 ret = trace_define_field(call, "unsigned long", arg, offset,
f3ff4ed51edb59 Steven Rostedt 2026-03-10 661 sizeof(unsigned long), 0, FILTER_OTHER);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 662 if (ret)
f3ff4ed51edb59 Steven Rostedt 2026-03-10 663 goto free;
f3ff4ed51edb59 Steven Rostedt 2026-03-10 664 offset += sizeof(long);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 665
f3ff4ed51edb59 Steven Rostedt 2026-03-10 666 arg = kstrdup("__ts2", GFP_KERNEL);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 667 if (WARN_ON_ONCE(!arg))
f3ff4ed51edb59 Steven Rostedt 2026-03-10 668 return -ENOMEM;
f3ff4ed51edb59 Steven Rostedt 2026-03-10 669 ret = trace_define_field(call, "unsigned long", arg, offset,
f3ff4ed51edb59 Steven Rostedt 2026-03-10 670 sizeof(unsigned long), 0, FILTER_OTHER);
f3ff4ed51edb59 Steven Rostedt 2026-03-10 671 if (ret)
f3ff4ed51edb59 Steven Rostedt 2026-03-10 672 goto free;
f3ff4ed51edb59 Steven Rostedt 2026-03-10 673
f3ff4ed51edb59 Steven Rostedt 2026-03-10 674 return 0;
f3ff4ed51edb59 Steven Rostedt 2026-03-10 675
f3ff4ed51edb59 Steven Rostedt 2026-03-10 676 free:
15901aaefa1313 Steven Rostedt 2026-03-10 677 kfree(arg);
15901aaefa1313 Steven Rostedt 2026-03-10 678 return ret;
15901aaefa1313 Steven Rostedt 2026-03-10 679 }
15901aaefa1313 Steven Rostedt 2026-03-10 680
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-03-12 22:49 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2026-03-12 22:49 [PATCH v2 2/3] tracing: Update futex syscall trace event to show more commands kernel test robot
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2026-03-10 20:09 [PATCH v2 0/3] tracing: Read user data from futex system call trace event Steven Rostedt
2026-03-10 20:09 ` [PATCH v2 2/3] tracing: Update futex syscall trace event to show more commands Steven Rostedt
2026-03-12 5:34 ` Masami Hiramatsu
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