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) in a more modular way (follow-up patch does 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+cogfd4axrthr2gsi...@mail.gmail.com/ Signed-off-by: Bhupesh <bhup...@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/signal.h | 1 + include/trace/events/task.h | 2 ++ 6 files changed, 12 insertions(+), 1 deletion(-) diff --git a/include/linux/coredump.h b/include/linux/coredump.h index 68861da4cf7c..988b233dcc09 100644 --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -54,7 +54,8 @@ 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)); \ + memcpy(comm, current->comm, TASK_COMM_LEN); \ + comm[TASK_COMM_LEN - 1] = '\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 3e582d5e3a57..af40096a7114 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]", @@ -435,6 +437,7 @@ 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) @@ -454,6 +457,7 @@ 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) @@ -505,6 +509,7 @@ 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/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
