As Linus mentioned in [1], currently we have several memcpy() use-cases
which use 'current->comm' to copy the task name over to local copies.
For an example:
...
char comm[TASK_COMM_LEN];
memcpy(comm, current->comm, TASK_COMM_LEN);
...
These should be rather calling a wrappper like "get_task_array()",
which is implemented as:
static __always_inline void
__cstr_array_copy(char *dst,
const char *src, __kernel_size_t size)
{
memcpy(dst, src, size);
dst[size] = 0;
}
#define get_task_array(dst,src) \
__cstr_array_copy(dst, src, __must_be_array(dst))
The relevant 'memcpy()' users were identified using the following search
pattern:
$ git grep 'memcpy.*->comm\>'
[1]. https://lore.kernel.org/all/CAHk-=wi5c=_-FBGo_88CowJd_F-Gi6Ud9d=TALm65ReN7YjrMw@mail.gmail.com/
Signed-off-by: Bhupesh <bhupesh@igalia.com>
---
include/linux/coredump.h | 2 +-
include/linux/sched.h | 32 +++++++++++++++++++
include/linux/tracepoint.h | 4 +--
include/trace/events/block.h | 10 +++---
include/trace/events/oom.h | 2 +-
include/trace/events/osnoise.h | 2 +-
include/trace/events/sched.h | 13 ++++----
include/trace/events/signal.h | 2 +-
include/trace/events/task.h | 4 +--
tools/bpf/bpftool/pids.c | 6 ++--
.../bpf/test_kmods/bpf_testmod-events.h | 2 +-
11 files changed, 54 insertions(+), 25 deletions(-)
diff --git a/include/linux/coredump.h b/include/linux/coredump.h
index 68861da4cf7c..bcee0afc5eaf 100644
--- a/include/linux/coredump.h
+++ b/include/linux/coredump.h
@@ -54,7 +54,7 @@ extern void vfs_coredump(const kernel_siginfo_t *siginfo);
do { \
char comm[TASK_COMM_LEN]; \
/* This will always be NUL terminated. */ \
- memcpy(comm, current->comm, sizeof(comm)); \
+ get_task_array(comm, current->comm); \
printk_ratelimited(Level "coredump: %d(%*pE): " Format "\n", \
task_tgid_vnr(current), (int)strlen(comm), comm, ##__VA_ARGS__); \
} while (0) \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 97ea2ac2a97a..6602ec132297 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1960,12 +1960,44 @@ extern void wake_up_new_task(struct task_struct *tsk);
extern void kick_process(struct task_struct *tsk);
+/*
+ * - Why not use task_lock()?
+ * User space can randomly change their names anyway, so locking for readers
+ * doesn't make sense. For writers, locking is probably necessary, as a race
+ * condition could lead to long-term mixed results.
+ * The logic inside __set_task_comm() should ensure that the task comm is
+ * always NUL-terminated and zero-padded. Therefore the race condition between
+ * reader and writer is not an issue.
+ */
+
extern void __set_task_comm(struct task_struct *tsk, const char *from, bool exec);
#define set_task_comm(tsk, from) ({ \
BUILD_BUG_ON(sizeof(from) < TASK_COMM_LEN); \
__set_task_comm(tsk, from, false); \
})
+/*
+ * 'get_task_array' can be 'data-racy' in the destination and
+ * should not be used for cases where a 'stable NUL at the end'
+ * is needed. Its better to use strscpy and friends for such
+ * use-cases.
+ *
+ * It is suited mainly for a 'just copy comm to a constant-sized
+ * array' case - especially in performance sensitive use-cases,
+ * like tracing.
+ */
+
+static __always_inline void
+ __cstr_array_copy(char *dst, const char *src,
+ __kernel_size_t size)
+{
+ memcpy(dst, src, size);
+ dst[size] = 0;
+}
+
+#define get_task_array(dst, src) \
+ __cstr_array_copy(dst, src, __must_be_array(dst))
+
static __always_inline void scheduler_ipi(void)
{
/*
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 826ce3f8e1f8..40e04cb660ce 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -570,10 +570,10 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
* *
*
* TP_fast_assign(
- * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
+ * get_task_array(__entry->next_comm, next->comm);
* __entry->prev_pid = prev->pid;
* __entry->prev_prio = prev->prio;
- * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
+ * get_task_array(__entry->prev_comm, prev->comm);
* __entry->next_pid = next->pid;
* __entry->next_prio = next->prio;
* ),
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 6aa79e2d799c..de1fe35333fc 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -213,7 +213,7 @@ DECLARE_EVENT_CLASS(block_rq,
blk_fill_rwbs(__entry->rwbs, rq->cmd_flags);
__get_str(cmd)[0] = '\0';
- memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, current->comm);
),
TP_printk("%d,%d %s %u (%s) %llu + %u %s,%u,%u [%s]",
@@ -351,7 +351,7 @@ DECLARE_EVENT_CLASS(block_bio,
__entry->sector = bio->bi_iter.bi_sector;
__entry->nr_sector = bio_sectors(bio);
blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
- memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, current->comm);
),
TP_printk("%d,%d %s %llu + %u [%s]",
@@ -434,7 +434,7 @@ TRACE_EVENT(block_plug,
),
TP_fast_assign(
- memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, current->comm);
),
TP_printk("[%s]", __entry->comm)
@@ -453,7 +453,7 @@ DECLARE_EVENT_CLASS(block_unplug,
TP_fast_assign(
__entry->nr_rq = depth;
- memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, current->comm);
),
TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)
@@ -504,7 +504,7 @@ TRACE_EVENT(block_split,
__entry->sector = bio->bi_iter.bi_sector;
__entry->new_sector = new_sector;
blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
- memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, current->comm);
),
TP_printk("%d,%d %s %llu / %llu [%s]",
diff --git a/include/trace/events/oom.h b/include/trace/events/oom.h
index 9f0a5d1482c4..31e5b7295188 100644
--- a/include/trace/events/oom.h
+++ b/include/trace/events/oom.h
@@ -23,7 +23,7 @@ TRACE_EVENT(oom_score_adj_update,
TP_fast_assign(
__entry->pid = task->pid;
- memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, task->comm);
__entry->oom_score_adj = task->signal->oom_score_adj;
),
diff --git a/include/trace/events/osnoise.h b/include/trace/events/osnoise.h
index 3f4273623801..f67f8b5eca75 100644
--- a/include/trace/events/osnoise.h
+++ b/include/trace/events/osnoise.h
@@ -116,7 +116,7 @@ TRACE_EVENT(thread_noise,
),
TP_fast_assign(
- memcpy(__entry->comm, t->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, t->comm);
__entry->pid = t->pid;
__entry->start = start;
__entry->duration = duration;
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 7b2645b50e78..66fe808f2654 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -152,7 +152,7 @@ DECLARE_EVENT_CLASS(sched_wakeup_template,
),
TP_fast_assign(
- memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, p->comm);
__entry->pid = p->pid;
__entry->prio = p->prio; /* XXX SCHED_DEADLINE */
__entry->target_cpu = task_cpu(p);
@@ -237,11 +237,11 @@ TRACE_EVENT(sched_switch,
),
TP_fast_assign(
- memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
+ get_task_array(__entry->prev_comm, prev->comm);
__entry->prev_pid = prev->pid;
__entry->prev_prio = prev->prio;
__entry->prev_state = __trace_sched_switch_state(preempt, prev_state, prev);
- memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
+ get_task_array(__entry->next_comm, next->comm);
__entry->next_pid = next->pid;
__entry->next_prio = next->prio;
/* XXX SCHED_DEADLINE */
@@ -346,7 +346,7 @@ TRACE_EVENT(sched_process_exit,
),
TP_fast_assign(
- memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, p->comm);
__entry->pid = p->pid;
__entry->prio = p->prio; /* XXX SCHED_DEADLINE */
__entry->group_dead = group_dead;
@@ -787,14 +787,13 @@ TRACE_EVENT(sched_skip_cpuset_numa,
),
TP_fast_assign(
- memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, tsk->comm);
__entry->pid = task_pid_nr(tsk);
__entry->tgid = task_tgid_nr(tsk);
__entry->ngid = task_numa_group_id(tsk);
BUILD_BUG_ON(sizeof(nodemask_t) != \
BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long));
- memcpy(__entry->mem_allowed, mem_allowed_ptr->bits,
- sizeof(__entry->mem_allowed));
+ get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
),
TP_printk("comm=%s pid=%d tgid=%d ngid=%d mem_nodes_allowed=%*pbl",
diff --git a/include/trace/events/signal.h b/include/trace/events/signal.h
index 1db7e4b07c01..0681dc5ab1de 100644
--- a/include/trace/events/signal.h
+++ b/include/trace/events/signal.h
@@ -67,7 +67,7 @@ TRACE_EVENT(signal_generate,
TP_fast_assign(
__entry->sig = sig;
TP_STORE_SIGINFO(__entry, info);
- memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, task->comm);
__entry->pid = task->pid;
__entry->group = group;
__entry->result = result;
diff --git a/include/trace/events/task.h b/include/trace/events/task.h
index af535b053033..9553946943a6 100644
--- a/include/trace/events/task.h
+++ b/include/trace/events/task.h
@@ -21,7 +21,7 @@ TRACE_EVENT(task_newtask,
TP_fast_assign(
__entry->pid = task->pid;
- memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, task->comm);
__entry->clone_flags = clone_flags;
__entry->oom_score_adj = task->signal->oom_score_adj;
),
@@ -44,7 +44,7 @@ TRACE_EVENT(task_rename,
),
TP_fast_assign(
- memcpy(entry->oldcomm, task->comm, TASK_COMM_LEN);
+ get_task_array(entry->oldcomm, task->comm);
strscpy(entry->newcomm, comm, TASK_COMM_LEN);
__entry->oom_score_adj = task->signal->oom_score_adj;
),
diff --git a/tools/bpf/bpftool/pids.c b/tools/bpf/bpftool/pids.c
index 23f488cf1740..a5d339cb8ca3 100644
--- a/tools/bpf/bpftool/pids.c
+++ b/tools/bpf/bpftool/pids.c
@@ -53,8 +53,7 @@ static void add_ref(struct hashmap *map, struct pid_iter_entry *e)
refs->refs = tmp;
ref = &refs->refs[refs->ref_cnt];
ref->pid = e->pid;
- memcpy(ref->comm, e->comm, sizeof(ref->comm));
- ref->comm[sizeof(ref->comm) - 1] = '\0';
+ get_task_array(ref->comm, e->comm);
refs->ref_cnt++;
return;
@@ -77,8 +76,7 @@ static void add_ref(struct hashmap *map, struct pid_iter_entry *e)
}
ref = &refs->refs[0];
ref->pid = e->pid;
- memcpy(ref->comm, e->comm, sizeof(ref->comm));
- ref->comm[sizeof(ref->comm) - 1] = '\0';
+ get_task_array(ref->comm, e->comm);
refs->ref_cnt = 1;
refs->has_bpf_cookie = e->has_bpf_cookie;
refs->bpf_cookie = e->bpf_cookie;
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod-events.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod-events.h
index aeef86b3da74..81880748550f 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod-events.h
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod-events.h
@@ -20,7 +20,7 @@ TRACE_EVENT(bpf_testmod_test_read,
),
TP_fast_assign(
__entry->pid = task->pid;
- memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ get_task_array(__entry->comm, task->comm);
__entry->off = ctx->off;
__entry->len = ctx->len;
),
--
2.38.1Hi Bhupesh,
kernel test robot noticed the following build errors:
[auto build test ERROR on next-20250808]
[cannot apply to trace/for-next tip/sched/core brauner-vfs/vfs.all linus/master v6.17-rc1 v6.16 v6.16-rc7 v6.17-rc1]
[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/Bhupesh/exec-Remove-obsolete-comments/20250811-144920
base: next-20250808
patch link: https://lore.kernel.org/r/20250811064609.918593-5-bhupesh%40igalia.com
patch subject: [PATCH v7 4/4] treewide: Switch memcpy() users of 'task->comm' to a more safer implementation
config: x86_64-buildonly-randconfig-001-20250811 (https://download.01.org/0day-ci/archive/20250812/202508120011.j4Pmr6Rf-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250812/202508120011.j4Pmr6Rf-lkp@intel.com/reproduce)
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>
| Closes: https://lore.kernel.org/oe-kbuild-all/202508120011.j4Pmr6Rf-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from include/trace/define_trace.h:132,
from include/trace/events/sched.h:901,
from kernel/sched/core.c:85:
include/trace/events/sched.h: In function 'do_trace_event_raw_event_sched_skip_cpuset_numa':
>> include/trace/events/sched.h:796:39: error: passing argument 1 of '__cstr_array_copy' from incompatible pointer type [-Werror=incompatible-pointer-types]
796 | get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
include/trace/trace_events.h:427:11: note: in definition of macro '__DECLARE_EVENT_CLASS'
427 | { assign; } \
| ^~~~~~
include/trace/trace_events.h:435:23: note: in expansion of macro 'PARAMS'
435 | PARAMS(assign), PARAMS(print)) \
| ^~~~~~
include/trace/trace_events.h:40:9: note: in expansion of macro 'DECLARE_EVENT_CLASS'
40 | DECLARE_EVENT_CLASS(name, \
| ^~~~~~~~~~~~~~~~~~~
include/trace/trace_events.h:44:30: note: in expansion of macro 'PARAMS'
44 | PARAMS(assign), \
| ^~~~~~
include/trace/events/sched.h:775:1: note: in expansion of macro 'TRACE_EVENT'
775 | TRACE_EVENT(sched_skip_cpuset_numa,
| ^~~~~~~~~~~
include/trace/events/sched.h:789:9: note: in expansion of macro 'TP_fast_assign'
789 | TP_fast_assign(
| ^~~~~~~~~~~~~~
include/trace/events/sched.h:796:17: note: in expansion of macro 'get_task_array'
796 | get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
| ^~~~~~~~~~~~~~
In file included from include/linux/percpu.h:12,
from arch/x86/include/asm/msr.h:16,
from arch/x86/include/asm/tsc.h:11,
from arch/x86/include/asm/timex.h:6,
from include/linux/timex.h:67,
from include/linux/time32.h:13,
from include/linux/time.h:60,
from include/linux/stat.h:19,
from include/linux/fs.h:11,
from include/linux/highmem.h:5,
from kernel/sched/core.c:10:
include/linux/sched.h:1991:33: note: expected 'char *' but argument is of type 'long unsigned int *'
1991 | __cstr_array_copy(char *dst, const char *src,
| ~~~~~~^~~
include/trace/events/sched.h:796:69: error: passing argument 2 of '__cstr_array_copy' from incompatible pointer type [-Werror=incompatible-pointer-types]
796 | get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
| ~~~~~~~~~~~~~~~^~~~~~
| |
| long unsigned int *
include/trace/trace_events.h:427:11: note: in definition of macro '__DECLARE_EVENT_CLASS'
427 | { assign; } \
| ^~~~~~
include/trace/trace_events.h:435:23: note: in expansion of macro 'PARAMS'
435 | PARAMS(assign), PARAMS(print)) \
| ^~~~~~
include/trace/trace_events.h:40:9: note: in expansion of macro 'DECLARE_EVENT_CLASS'
40 | DECLARE_EVENT_CLASS(name, \
| ^~~~~~~~~~~~~~~~~~~
include/trace/trace_events.h:44:30: note: in expansion of macro 'PARAMS'
44 | PARAMS(assign), \
| ^~~~~~
include/trace/events/sched.h:775:1: note: in expansion of macro 'TRACE_EVENT'
775 | TRACE_EVENT(sched_skip_cpuset_numa,
| ^~~~~~~~~~~
include/trace/events/sched.h:789:9: note: in expansion of macro 'TP_fast_assign'
789 | TP_fast_assign(
| ^~~~~~~~~~~~~~
include/trace/events/sched.h:796:17: note: in expansion of macro 'get_task_array'
796 | get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
| ^~~~~~~~~~~~~~
include/linux/sched.h:1991:50: note: expected 'const char *' but argument is of type 'long unsigned int *'
1991 | __cstr_array_copy(char *dst, const char *src,
| ~~~~~~~~~~~~^~~
In file included from include/trace/define_trace.h:133:
include/trace/events/sched.h: In function 'do_perf_trace_sched_skip_cpuset_numa':
>> include/trace/events/sched.h:796:39: error: passing argument 1 of '__cstr_array_copy' from incompatible pointer type [-Werror=incompatible-pointer-types]
796 | get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
include/trace/perf.h:51:11: note: in definition of macro '__DECLARE_EVENT_CLASS'
51 | { assign; } \
| ^~~~~~
include/trace/perf.h:67:23: note: in expansion of macro 'PARAMS'
67 | PARAMS(assign), PARAMS(print)) \
| ^~~~~~
include/trace/trace_events.h:40:9: note: in expansion of macro 'DECLARE_EVENT_CLASS'
40 | DECLARE_EVENT_CLASS(name, \
| ^~~~~~~~~~~~~~~~~~~
include/trace/trace_events.h:44:30: note: in expansion of macro 'PARAMS'
44 | PARAMS(assign), \
| ^~~~~~
include/trace/events/sched.h:775:1: note: in expansion of macro 'TRACE_EVENT'
775 | TRACE_EVENT(sched_skip_cpuset_numa,
| ^~~~~~~~~~~
include/trace/events/sched.h:789:9: note: in expansion of macro 'TP_fast_assign'
789 | TP_fast_assign(
| ^~~~~~~~~~~~~~
include/trace/events/sched.h:796:17: note: in expansion of macro 'get_task_array'
796 | get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
| ^~~~~~~~~~~~~~
include/linux/sched.h:1991:33: note: expected 'char *' but argument is of type 'long unsigned int *'
1991 | __cstr_array_copy(char *dst, const char *src,
| ~~~~~~^~~
include/trace/events/sched.h:796:69: error: passing argument 2 of '__cstr_array_copy' from incompatible pointer type [-Werror=incompatible-pointer-types]
796 | get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
| ~~~~~~~~~~~~~~~^~~~~~
| |
| long unsigned int *
include/trace/perf.h:51:11: note: in definition of macro '__DECLARE_EVENT_CLASS'
51 | { assign; } \
| ^~~~~~
include/trace/perf.h:67:23: note: in expansion of macro 'PARAMS'
67 | PARAMS(assign), PARAMS(print)) \
| ^~~~~~
include/trace/trace_events.h:40:9: note: in expansion of macro 'DECLARE_EVENT_CLASS'
40 | DECLARE_EVENT_CLASS(name, \
| ^~~~~~~~~~~~~~~~~~~
include/trace/trace_events.h:44:30: note: in expansion of macro 'PARAMS'
44 | PARAMS(assign), \
| ^~~~~~
include/trace/events/sched.h:775:1: note: in expansion of macro 'TRACE_EVENT'
775 | TRACE_EVENT(sched_skip_cpuset_numa,
| ^~~~~~~~~~~
include/trace/events/sched.h:789:9: note: in expansion of macro 'TP_fast_assign'
789 | TP_fast_assign(
| ^~~~~~~~~~~~~~
include/trace/events/sched.h:796:17: note: in expansion of macro 'get_task_array'
796 | get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
| ^~~~~~~~~~~~~~
include/linux/sched.h:1991:50: note: expected 'const char *' but argument is of type 'long unsigned int *'
1991 | __cstr_array_copy(char *dst, const char *src,
| ~~~~~~~~~~~~^~~
cc1: some warnings being treated as errors
vim +/__cstr_array_copy +796 include/trace/events/sched.h
776
777 TP_PROTO(struct task_struct *tsk, nodemask_t *mem_allowed_ptr),
778
779 TP_ARGS(tsk, mem_allowed_ptr),
780
781 TP_STRUCT__entry(
782 __array( char, comm, TASK_COMM_LEN )
783 __field( pid_t, pid )
784 __field( pid_t, tgid )
785 __field( pid_t, ngid )
786 __array( unsigned long, mem_allowed, BITS_TO_LONGS(MAX_NUMNODES))
787 ),
788
789 TP_fast_assign(
790 get_task_array(__entry->comm, tsk->comm);
791 __entry->pid = task_pid_nr(tsk);
792 __entry->tgid = task_tgid_nr(tsk);
793 __entry->ngid = task_numa_group_id(tsk);
794 BUILD_BUG_ON(sizeof(nodemask_t) != \
795 BITS_TO_LONGS(MAX_NUMNODES) * sizeof(long));
> 796 get_task_array(__entry->mem_allowed, mem_allowed_ptr->bits);
797 ),
798
799 TP_printk("comm=%s pid=%d tgid=%d ngid=%d mem_nodes_allowed=%*pbl",
800 __entry->comm,
801 __entry->pid,
802 __entry->tgid,
803 __entry->ngid,
804 MAX_NUMNODES, __entry->mem_allowed)
805 );
806 #endif /* CONFIG_NUMA_BALANCING */
807
808 /*
809 * Tracepoint for waking a polling cpu without an IPI.
810 */
811 TRACE_EVENT(sched_wake_idle_without_ipi,
812
813 TP_PROTO(int cpu),
814
815 TP_ARGS(cpu),
816
817 TP_STRUCT__entry(
818 __field( int, cpu )
819 ),
820
821 TP_fast_assign(
822 __entry->cpu = cpu;
823 ),
824
825 TP_printk("cpu=%d", __entry->cpu)
826 );
827
828 /*
829 * Following tracepoints are not exported in tracefs and provide hooking
830 * mechanisms only for testing and debugging purposes.
831 */
832 DECLARE_TRACE(pelt_cfs,
833 TP_PROTO(struct cfs_rq *cfs_rq),
834 TP_ARGS(cfs_rq));
835
836 DECLARE_TRACE(pelt_rt,
837 TP_PROTO(struct rq *rq),
838 TP_ARGS(rq));
839
840 DECLARE_TRACE(pelt_dl,
841 TP_PROTO(struct rq *rq),
842 TP_ARGS(rq));
843
844 DECLARE_TRACE(pelt_hw,
845 TP_PROTO(struct rq *rq),
846 TP_ARGS(rq));
847
848 DECLARE_TRACE(pelt_irq,
849 TP_PROTO(struct rq *rq),
850 TP_ARGS(rq));
851
852 DECLARE_TRACE(pelt_se,
853 TP_PROTO(struct sched_entity *se),
854 TP_ARGS(se));
855
856 DECLARE_TRACE(sched_cpu_capacity,
857 TP_PROTO(struct rq *rq),
858 TP_ARGS(rq));
859
860 DECLARE_TRACE(sched_overutilized,
861 TP_PROTO(struct root_domain *rd, bool overutilized),
862 TP_ARGS(rd, overutilized));
863
864 DECLARE_TRACE(sched_util_est_cfs,
865 TP_PROTO(struct cfs_rq *cfs_rq),
866 TP_ARGS(cfs_rq));
867
868 DECLARE_TRACE(sched_util_est_se,
869 TP_PROTO(struct sched_entity *se),
870 TP_ARGS(se));
871
872 DECLARE_TRACE(sched_update_nr_running,
873 TP_PROTO(struct rq *rq, int change),
874 TP_ARGS(rq, change));
875
876 DECLARE_TRACE(sched_compute_energy,
877 TP_PROTO(struct task_struct *p, int dst_cpu, unsigned long energy,
878 unsigned long max_util, unsigned long busy_time),
879 TP_ARGS(p, dst_cpu, energy, max_util, busy_time));
880
881 DECLARE_TRACE(sched_entry,
882 TP_PROTO(bool preempt),
883 TP_ARGS(preempt));
884
885 DECLARE_TRACE(sched_exit,
886 TP_PROTO(bool is_switch),
887 TP_ARGS(is_switch));
888
889 DECLARE_TRACE_CONDITION(sched_set_state,
890 TP_PROTO(struct task_struct *tsk, int state),
891 TP_ARGS(tsk, state),
892 TP_CONDITION(!!(tsk->__state) != !!state));
893
894 DECLARE_TRACE(sched_set_need_resched,
895 TP_PROTO(struct task_struct *tsk, int cpu, int tif),
896 TP_ARGS(tsk, cpu, tif));
897
898 #endif /* _TRACE_SCHED_H */
899
900 /* This part must be outside protection */
> 901 #include <trace/define_trace.h>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Mon, Aug 11, 2025 at 12:16:09PM +0530, Bhupesh wrote:
> As Linus mentioned in [1], currently we have several memcpy() use-cases
> which use 'current->comm' to copy the task name over to local copies.
> For an example:
>
> ...
> char comm[TASK_COMM_LEN];
> memcpy(comm, current->comm, TASK_COMM_LEN);
> ...
>
> These should be rather calling a wrappper like "get_task_array()",
> which is implemented as:
>
> static __always_inline void
> __cstr_array_copy(char *dst,
> const char *src, __kernel_size_t size)
> {
> memcpy(dst, src, size);
> dst[size] = 0;
> }
>
> #define get_task_array(dst,src) \
> __cstr_array_copy(dst, src, __must_be_array(dst))
>
> The relevant 'memcpy()' users were identified using the following search
> pattern:
> $ git grep 'memcpy.*->comm\>'
> [1]. https://lore.kernel.org/all/CAHk-=wi5c=_-FBGo_88CowJd_F-Gi6Ud9d=TALm65ReN7YjrMw@mail.gmail.com/
>
> Signed-off-by: Bhupesh <bhupesh@igalia.com>
Same suggestion, make it a Link tag.
--
With Best Regards,
Andy Shevchenko
© 2016 - 2026 Red Hat, Inc.