From: Bhupesh <bhupesh@igalia.com>
To: akpm@linux-foundation.org
Cc: bhupesh@igalia.com, kernel-dev@igalia.com,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, oliver.sang@intel.com, lkp@intel.com,
laoar.shao@gmail.com, pmladek@suse.com, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com,
alexei.starovoitov@gmail.com, andrii.nakryiko@gmail.com,
mirq-linux@rere.qmqm.pl, peterz@infradead.org,
willy@infradead.org, david@redhat.com, viro@zeniv.linux.org.uk,
keescook@chromium.org, ebiederm@xmission.com, brauner@kernel.org,
jack@suse.cz, mingo@redhat.com, juri.lelli@redhat.com,
bsegall@google.com, mgorman@suse.de, vschneid@redhat.com
Subject: [PATCH v3 2/3] treewide: Switch memcpy() users of 'task->comm' to a more safer implementation
Date: Wed, 7 May 2025 16:34:43 +0530 [thread overview]
Message-ID: <20250507110444.963779-3-bhupesh@igalia.com> (raw)
In-Reply-To: <20250507110444.963779-1-bhupesh@igalia.com>
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 modified so that we can later implement approaches
to handle the task->comm's 16-byte length limitation (TASK_COMM_LEN)
is a more modular way (follow-up patches do the same):
...
char comm[TASK_COMM_LEN];
memcpy(comm, current->comm, TASK_COMM_LEN);
comm[TASK_COMM_LEN - 1] = 0;
...
The relevant 'memcpy()' users were identified using the following search
pattern:
$ git grep 'memcpy.*->comm\>'
[1]. https://lore.kernel.org/all/CAHk-=wjAmmHUg6vho1KjzQi2=psR30+CogFd4aXrThr2gsiS4g@mail.gmail.com/
Signed-off-by: Bhupesh <bhupesh@igalia.com>
---
include/linux/coredump.h | 3 ++-
include/trace/events/block.h | 5 +++++
include/trace/events/oom.h | 1 +
include/trace/events/osnoise.h | 1 +
include/trace/events/sched.h | 13 +++++++++++++
include/trace/events/signal.h | 1 +
include/trace/events/task.h | 2 ++
7 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/include/linux/coredump.h b/include/linux/coredump.h
index 77e6e195d1d6..058ae3f2bec8 100644
--- a/include/linux/coredump.h
+++ b/include/linux/coredump.h
@@ -53,7 +53,8 @@ extern void do_coredump(const kernel_siginfo_t *siginfo);
do { \
char comm[TASK_COMM_LEN]; \
/* This will always be NUL terminated. */ \
- memcpy(comm, current->comm, sizeof(comm)); \
+ memcpy(comm, current->comm, TASK_COMM_LEN); \
+ comm[TASK_COMM_LEN] = '\0'; \
printk_ratelimited(Level "coredump: %d(%*pE): " Format "\n", \
task_tgid_vnr(current), (int)strlen(comm), comm, ##__VA_ARGS__); \
} while (0) \
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index bd0ea07338eb..94a941ac2034 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -214,6 +214,7 @@ 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);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
),
TP_printk("%d,%d %s %u (%s) %llu + %u %s,%u,%u [%s]",
@@ -352,6 +353,7 @@ DECLARE_EVENT_CLASS(block_bio,
__entry->nr_sector = bio_sectors(bio);
blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
),
TP_printk("%d,%d %s %llu + %u [%s]",
@@ -439,6 +441,7 @@ TRACE_EVENT(block_plug,
TP_fast_assign(
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
),
TP_printk("[%s]", __entry->comm)
@@ -458,6 +461,7 @@ DECLARE_EVENT_CLASS(block_unplug,
TP_fast_assign(
__entry->nr_rq = depth;
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
),
TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)
@@ -509,6 +513,7 @@ TRACE_EVENT(block_split,
__entry->new_sector = new_sector;
blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
),
TP_printk("%d,%d %s %llu / %llu [%s]",
diff --git a/include/trace/events/oom.h b/include/trace/events/oom.h
index 9f0a5d1482c4..a5641ed4285f 100644
--- a/include/trace/events/oom.h
+++ b/include/trace/events/oom.h
@@ -24,6 +24,7 @@ TRACE_EVENT(oom_score_adj_update,
TP_fast_assign(
__entry->pid = task->pid;
memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__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..0321b3f8d532 100644
--- a/include/trace/events/osnoise.h
+++ b/include/trace/events/osnoise.h
@@ -117,6 +117,7 @@ TRACE_EVENT(thread_noise,
TP_fast_assign(
memcpy(__entry->comm, t->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__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 8994e97d86c1..3126d44c43ee 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -26,6 +26,7 @@ TRACE_EVENT(sched_kthread_stop,
TP_fast_assign(
memcpy(__entry->comm, t->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = t->pid;
),
@@ -153,6 +154,7 @@ DECLARE_EVENT_CLASS(sched_wakeup_template,
TP_fast_assign(
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = p->pid;
__entry->prio = p->prio; /* XXX SCHED_DEADLINE */
__entry->target_cpu = task_cpu(p);
@@ -238,10 +240,12 @@ TRACE_EVENT(sched_switch,
TP_fast_assign(
memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__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);
+ __entry->next_comm[TASK_COMM_LEN - 1] = '\0';
__entry->next_pid = next->pid;
__entry->next_prio = next->prio;
/* XXX SCHED_DEADLINE */
@@ -285,6 +289,7 @@ TRACE_EVENT(sched_migrate_task,
TP_fast_assign(
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = p->pid;
__entry->prio = p->prio; /* XXX SCHED_DEADLINE */
__entry->orig_cpu = task_cpu(p);
@@ -310,6 +315,7 @@ DECLARE_EVENT_CLASS(sched_process_template,
TP_fast_assign(
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = p->pid;
__entry->prio = p->prio; /* XXX SCHED_DEADLINE */
),
@@ -356,6 +362,7 @@ TRACE_EVENT(sched_process_wait,
TP_fast_assign(
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = pid_nr(pid);
__entry->prio = current->prio; /* XXX SCHED_DEADLINE */
),
@@ -382,8 +389,10 @@ TRACE_EVENT(sched_process_fork,
TP_fast_assign(
memcpy(__entry->parent_comm, parent->comm, TASK_COMM_LEN);
+ __entry->parent_comm[TASK_COMM_LEN - 1] = '\0';
__entry->parent_pid = parent->pid;
memcpy(__entry->child_comm, child->comm, TASK_COMM_LEN);
+ __entry->child_comm[TASK_COMM_LEN - 1] = '\0';
__entry->child_pid = child->pid;
),
@@ -480,6 +489,7 @@ DECLARE_EVENT_CLASS_SCHEDSTAT(sched_stat_template,
TP_fast_assign(
memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = tsk->pid;
__entry->delay = delay;
),
@@ -538,6 +548,7 @@ DECLARE_EVENT_CLASS(sched_stat_runtime,
TP_fast_assign(
memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = tsk->pid;
__entry->runtime = runtime;
),
@@ -570,6 +581,7 @@ TRACE_EVENT(sched_pi_setprio,
TP_fast_assign(
memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = tsk->pid;
__entry->oldprio = tsk->prio;
__entry->newprio = pi_task ?
@@ -595,6 +607,7 @@ TRACE_EVENT(sched_process_hang,
TP_fast_assign(
memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->pid = tsk->pid;
),
diff --git a/include/trace/events/signal.h b/include/trace/events/signal.h
index 1db7e4b07c01..7f490e553db5 100644
--- a/include/trace/events/signal.h
+++ b/include/trace/events/signal.h
@@ -68,6 +68,7 @@ TRACE_EVENT(signal_generate,
__entry->sig = sig;
TP_STORE_SIGINFO(__entry, info);
memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__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..4ddf21b69372 100644
--- a/include/trace/events/task.h
+++ b/include/trace/events/task.h
@@ -22,6 +22,7 @@ TRACE_EVENT(task_newtask,
TP_fast_assign(
__entry->pid = task->pid;
memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ __entry->comm[TASK_COMM_LEN - 1] = '\0';
__entry->clone_flags = clone_flags;
__entry->oom_score_adj = task->signal->oom_score_adj;
),
@@ -45,6 +46,7 @@ TRACE_EVENT(task_rename,
TP_fast_assign(
memcpy(entry->oldcomm, task->comm, TASK_COMM_LEN);
+ entry->oldcomm[TASK_COMM_LEN - 1] = '\0';
strscpy(entry->newcomm, comm, TASK_COMM_LEN);
__entry->oom_score_adj = task->signal->oom_score_adj;
),
--
2.38.1
next prev parent reply other threads:[~2025-05-07 11:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-07 11:04 [PATCH v3 0/3] Add support for long task name Bhupesh
2025-05-07 11:04 ` [PATCH v3 1/3] exec: Remove obsolete comments Bhupesh
2025-05-07 11:04 ` Bhupesh [this message]
2025-05-07 12:29 ` [PATCH v3 2/3] treewide: Switch memcpy() users of 'task->comm' to a more safer implementation Petr Mladek
2025-05-08 8:17 ` Bhupesh Sharma
2025-05-08 8:22 ` Bhupesh Sharma
2025-05-08 14:02 ` Steven Rostedt
2025-05-08 12:21 ` kernel test robot
2025-05-07 11:04 ` [PATCH v3 3/3] exec: Add support for 64 byte 'tsk->real_comm' Bhupesh
2025-05-07 12:54 ` Petr Mladek
2025-05-07 17:23 ` Steven Rostedt
2025-05-08 8:08 ` Bhupesh Sharma
2025-05-08 13:58 ` Steven Rostedt
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