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b=BMWp8pD7b9GiEYM/tFJo1TnmAV Vc9hHbhfmKolOyJCKbBRqSIC4CjK59oqtpEVzZ4TBBJ+lNf628BnUHtepubkcq1W7FdVmQaqxOrOo PDKmL9ueul+Azb2iulfgVVYyI0CboZGmrTszyAHcAKXbqXbFT50OhNwmgj4GcgQHDN6uweDRRdyLw z22GvTK7IQ09Rxx/TLpaVz4ESQDBCwAD5X+iWk2IG2oachNyc4j5/Pci41Yuv9C+QqHjhJJskWOdT iqGC5p78QFQI7QoaWRX8QAUCbNSpR4TOKMkOFqmNW/+oTxc/f8Y6YiCGeDzSW5LZChJhAvWpkLhjB wmokEYVQ==; Received: from [223.233.68.152] (helo=localhost.localdomain) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1up2Qv-00HBmV-UT; Thu, 21 Aug 2025 12:22:14 +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 v8 2/5] include: Set tsk->comm length to 64 bytes Date: Thu, 21 Aug 2025 15:51:49 +0530 Message-Id: <20250821102152.323367-3-bhupesh@igalia.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20250821102152.323367-1-bhupesh@igalia.com> References: <20250821102152.323367-1-bhupesh@igalia.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 64B9FC000A X-Stat-Signature: ddkf3sktt5nhjrb3tub6k1duohek9mpo X-Rspam-User: X-HE-Tag: 1755771738-339688 X-HE-Meta: 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 1LpcBmX+ B9eh8Sci9RknXRkNVG5JKfUhM/WvA2Y/FbxT75k205KJ1ujZPqldzWDhnUBFVehaQxp4OzK8ry2bOaxIgbkbTp+T9UCyzJaPgtBxa2bC5FpOl2hBLcqTI7MyL2GaO5EANOIlh21XI8UVfNaeYRnhSQPoc3bEmf8cGQ0u/5e8rsNsinouEkaBNGUEozl+hjT6orP6lJxlbPTlt4UsZQ61tM0SAsvrvXBufbIsZ2qTqmnZk6azKFbsMbOp+1FRR8/HGpA0vgYIdgPGZe6ltCXpP/6IuvKcXpWLzCwGnfPyUnuCrQb5GYPdYb1m8dAj15SExMGg11Q2Y1F0ZYA0h0r+6gXhTFSQD4lRkajdWdQ8Rj5+FnNzcm1JCmXHjFo2IcR90yvvV 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 24216259cda4..bcebc5622e07 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