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b=ptqdBLk0JKXdgsD1MQ7pDWNbTJ Yx6u6119QunQo0/L3znvKKPWvfMTw2okCRnwrEiRIRokDj1xoz/hYlOpd6xAEXBuoefl8ebPAJWfM a8W4kh0bCi0vufydf+xHW33x3Q/dIONhTo01K5Mh3sDrHL18fF1d6WTvbZ/IWAENhbHLW7EY+r0Cg GhV4G6bw1PCYjifGJuvX/EesWsCX6t4y+2t9SWGNtas36iC45P42cXDjqAlINGwf/eDK2ygbczQdR aj3YnkYVkBcFXcsTFgwnJxeQCrFVIvvVxF2F6+Fa9hUOmoxA1WuzkDINqs1aLpAX/ewJv9rhHknHu FwX5swJQ==; Received: from [223.233.69.163] (helo=localhost.localdomain) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1ulMIn-00Cdun-Li; Mon, 11 Aug 2025 08:46:38 +0200 From: Bhupesh 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, linux-trace-kernel@vger.kernel.org, kees@kernel.org, torvalds@linux-foundation.org Subject: [PATCH v7 2/4] include: Set tsk->comm length to 64 bytes Date: Mon, 11 Aug 2025 12:16:07 +0530 Message-Id: <20250811064609.918593-3-bhupesh@igalia.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20250811064609.918593-1-bhupesh@igalia.com> References: <20250811064609.918593-1-bhupesh@igalia.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 86475180006 X-Stat-Signature: rps9ki33fkqqtmn8cpkda7dss1m6hbxw X-Rspam-User: X-HE-Tag: 1754894802-988357 X-HE-Meta: U2FsdGVkX1+8c87K2A3dsed4GNyZkDNyRcQHmnlUdBGmu2O8RcNDG75BuMdNuqwCxexaExL+DGnWj6U8F3ngimxubDakt2mq3YXIYCjzGOR+EkqXrf7BMki6TblSUJJGfrVbRlIdIQgxiUUANrVmviOnrNf+6mEcffjboNhI4/WjoTpNy4Ff6YfqxDOA5Y8esk+FSf6Vgl7LMsxjyEuBqvaJ5T8+1/rjQH7cOeDtdmtsAFQf8C0p0vUUjuUuhEdP5lJ+G/XSzHYLPyJxvjE59u0MVcP/+GQFjIs+Vj4R3Ud5GgtZoSEMsfan8bDlOF/QBlC4cQgzA96OPdpHTAAe2ez0CmZAmL5r8fffRPWpqIj91zOfS1IgWWETX60/sRKfuba5O2lET2cfTuVo5aYjsqa+zKarRmlPJcs1qP4kvMYbhM8udvFCQe5fABRuGN7KHw1Fdnl0CqsF8ZvRpUU8+ZlTuaXCvndrCIzPQ41ToktTS9wuI/0HNsVu0pzP+YWMUTIPCvvo8P8PIw72MDZLihpAM+CpuAnx4mLPCQ3Dgf/cKqpgZN3JoASL6E8i+uAwgEZgZ+eqAdlMwndLC4CUO9LxU5CiOP3zoHqdukCJMt9jZFzChRxaouBIk8+fXT6WleuIyHphPx+15ymM2XUa95nUpj8y+N/vltudNjKlIPfLXvn7jsHyh1BKMRBZppHI6Y1kgKHVGO9Kgw9IyTMtEcm1rgFpiKkMElszXfbt++uLtYj6D8Fug1dSLnfAVwerDy0eCi/smgOpeAw5eRgyxqnQJEG2pujDes+c6xoTtA6X9xIek+UIgt4evBi5dpJTt+npN/jEQcVowivej+RScMw/oFTx7s9CZjU/lb5CUzUxBkxedK/79QN+UPML4Niv4nOeP9v2ZrbMiwNQ66ZAmF1QpvpEhvrOATV1LNKX3WVzsn0uwTKTdCbBZvIlPvUJykfH7RqkEItyPimJivI vbmYQK3g oL6VDBStUP5GQDOhd9XKckyRK8GzVVIZCWGf7rKlUM4rVTzw/nUi8PvTrntG1wjiCpoySerp137SyTcb2HUvE1xv47+1PCYlOKPAijwdEmydC/xp8Y7xVVRjXIhhcsdcal92UiqE/5f0SWWAzjAaNGLK0wVd1izr4VaEtWfwcTH1Ai43FrPTLC8b5bcd2zcr2x12jJvhtsMMIha6UYlcKW5dkV8YMcPIIX0/6izL0U1TmlUiwDZ0Zx2DXh4FjAUJExNwI6BPf0ZbQuRgwIZiBn7do+Jdvl1su6lMeW73jfriWcn0BR6f3EFgxWVra3NaH5U5Lk4hL+xBRrYUB0wgAfJYCxAsVZP40CIK7NQwGlxcwv/1xcP/wjbYkRsBjjlOpwssl X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Historically due to the 16-byte length of TASK_COMM_LEN, the users of 'tsk->comm' are restricted to use a fixed-size target buffer also of TASK_COMM_LEN for 'memcpy()' like use-cases. To fix the same, we now use a 64-byte TASK_COMM_EXT_LEN and set the comm element inside 'task_struct' to the same length: struct task_struct { ..... char comm[TASK_COMM_EXT_LEN]; ..... }; where TASK_COMM_EXT_LEN is 64-bytes. Note, that the existing users have not been modified to migrate to 'TASK_COMM_EXT_LEN', in case they have hard-coded expectations of dealing with only a 'TASK_COMM_LEN' long 'tsk->comm'. Signed-off-by: Bhupesh --- include/linux/sched.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 35f1ef06eb6c..87e9dfaf61ac 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -318,6 +318,7 @@ struct user_event_mm; */ enum { TASK_COMM_LEN = 16, + TASK_COMM_EXT_LEN = 64, }; extern void sched_tick(void); @@ -1162,7 +1163,7 @@ struct task_struct { * - logic inside set_task_comm() will ensure it is always NUL-terminated and * zero-padded */ - char comm[TASK_COMM_LEN]; + char comm[TASK_COMM_EXT_LEN]; struct nameidata *nameidata; @@ -1961,7 +1962,7 @@ extern void kick_process(struct task_struct *tsk); 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); \ + BUILD_BUG_ON(sizeof(from) < TASK_COMM_LEN); \ __set_task_comm(tsk, from, false); \ }) -- 2.38.1