From: Yafang Shao <laoar.shao@gmail.com>
To: akpm@linux-foundation.org, keescook@chromium.org,
rostedt@goodmis.org, mathieu.desnoyers@efficios.com,
arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org,
viro@zeniv.linux.org.uk, valentin.schneider@arm.com,
qiang.zhang@windriver.com, robdclark@chromium.org,
christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
davem@davemloft.net, kuba@kernel.org, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com,
songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com,
kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com,
mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com,
jgg@ziepe.ca
Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, linux-perf-users@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, oliver.sang@intel.com,
lkp@intel.com, Yafang Shao <laoar.shao@gmail.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>
Subject: [PATCH v7 11/11] kernel/kthread: show a warning if kthread's comm is truncated
Date: Mon, 1 Nov 2021 06:04:19 +0000 [thread overview]
Message-ID: <20211101060419.4682-12-laoar.shao@gmail.com> (raw)
In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com>
Show a warning if task comm is truncated. Below is the result
of my test case:
truncated kthread comm:I-am-a-kthread-with-a-l (pid:178) by 8 characters
As we have extended task comm to 24, all the existing in-tree
kthreads/workqueues are not truncated anymore. So this warning will only
be printed for the newly introduced one if it has a long name.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
---
kernel/kthread.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 5b37a8567168..63f38d3a4f62 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -399,12 +399,17 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
if (!IS_ERR(task)) {
static const struct sched_param param = { .sched_priority = 0 };
char name[TASK_COMM_LEN];
+ int len;
/*
* task is already visible to other tasks, so updating
* COMM must be protected.
*/
- vsnprintf(name, sizeof(name), namefmt, args);
+ len = vsnprintf(name, sizeof(name), namefmt, args);
+ if (len >= TASK_COMM_LEN) {
+ pr_warn("truncated kthread comm:%s (pid:%d) by %d characters\n",
+ name, task->pid, len - TASK_COMM_LEN + 1);
+ }
set_task_comm(task, name);
/*
* root may have changed our (kthreadd's) priority or CPU mask.
--
2.17.1
next prev parent reply other threads:[~2021-11-01 6:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 6:04 [PATCH v7 00/11] extend task comm from 16 to 24 Yafang Shao
2021-11-01 6:04 ` [PATCH v7 01/11] fs/exec: make __set_task_comm always set a nul terminated string Yafang Shao
2021-11-01 6:04 ` [PATCH v7 02/11] fs/exec: make __get_task_comm always get " Yafang Shao
2021-11-01 6:04 ` [PATCH v7 03/11] sched.h: use __must_be_array instead of BUILD_BUG_ON in get_task_comm Yafang Shao
2021-11-01 6:04 ` [PATCH v7 04/11] drivers/infiniband: make setup_ctxt always get a nul terminated task comm Yafang Shao
2021-11-01 6:04 ` [PATCH v7 05/11] fs/binfmt_elf: make prpsinfo " Yafang Shao
2021-11-01 6:04 ` [PATCH v7 06/11] samples/bpf/test_overhead_kprobe_kern: make it adopt to task comm size change Yafang Shao
2021-11-01 6:04 ` [PATCH v7 07/11] tools/bpf/bpftool/skeleton: " Yafang Shao
2021-11-01 23:47 ` Andrii Nakryiko
2021-11-01 6:04 ` [PATCH v7 08/11] tools/perf/test: make perf test " Yafang Shao
2021-11-17 14:31 ` Arnaldo Carvalho de Melo
2021-11-18 14:18 ` Yafang Shao
2021-11-01 6:04 ` [PATCH v7 09/11] tools/testing/selftests/bpf: make it " Yafang Shao
2021-11-01 23:47 ` Andrii Nakryiko
2021-11-01 6:04 ` [PATCH v7 10/11] sched.h: extend task comm from 16 to 24 Yafang Shao
2021-11-01 6:04 ` Yafang Shao [this message]
2021-11-01 12:44 ` [PATCH v7 00/11] " Matthew Wilcox
2021-11-01 13:12 ` Yafang Shao
2021-11-01 14:07 ` Petr Mladek
2021-11-01 14:34 ` Yafang Shao
2021-11-01 16:02 ` Petr Mladek
2021-11-01 16:06 ` Steven Rostedt
2021-11-02 1:09 ` Yafang Shao
2021-11-02 1:18 ` Steven Rostedt
2021-11-02 1:26 ` Yafang Shao
2021-11-02 7:56 ` Petr Mladek
2021-11-02 13:48 ` Yafang Shao
2021-11-02 9:26 ` David Hildenbrand
2021-11-04 1:37 ` Michał Mirosław
2021-11-05 6:34 ` Yafang Shao
2021-11-05 23:57 ` Michał Mirosław
2021-11-06 9:12 ` Yafang Shao
2021-11-06 11:29 ` Michał Mirosław
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