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b=GT053E1gz6CXBmsRuLUeeUOtpZ 6eA3D/mixw8gzo+maEv5+OIfU9l6l1zpm7hNcECcQc97Y2Uo6qNtBbI9bu7B2qeu4nP2+DbqCect7 +zjIq1AQLb+dEZgY7qaQ2t2VyspHqmP2HsMoVM5BdOlERpTPwBCWEBlgc3/qNCUZ8n9qCihzT9LOi lksslbdaMs5Jqe0IdN1K2iRcqgnMKEunvX7/isGlu7tuUm64o3scA1BrNZUnEgAT3Tdz0XxirNtel jMh2a+QbAIEaP9yGzd0xamYvUdg2OP7Rsa5ZEk4cuNdocvwP1xQ9FqXMie0rBszM3c5oXfuc2GzRD biNb+Xcw==; Received: from [223.233.78.24] (helo=localhost.localdomain) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1uevBf-003BPU-Qi; Thu, 24 Jul 2025 14:36:40 +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 v6 2/3] treewide: Switch memcpy() users of 'task->comm' to a more safer implementation Date: Thu, 24 Jul 2025 18:06:11 +0530 Message-Id: <20250724123612.206110-3-bhupesh@igalia.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20250724123612.206110-1-bhupesh@igalia.com> References: <20250724123612.206110-1-bhupesh@igalia.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 3E8E518000E X-Stat-Signature: atma7esu6cenw66kq84rstkakdagos89 X-HE-Tag: 1753360604-285668 X-HE-Meta: U2FsdGVkX19sJ2Db2m+0Khk63Wbwq6lbIAI09lI3qgrJuIj/thggpnJXR7u+QIbL9HNOtso7KmIEjQeqoSVi2r6Ev14xDSYGNmGgstp3HdpU8+sZSWXq0rQT1tbLeqyspOXjP7+KwAuWT0wrFC0mOBpY+MScbK/Ps+sseRF38p0BFG29pLlrFiegMc7FCtTg+CC99ldtBB4VPfWb2KnhIo8P7YQef6T5FkIp0cHzCLHBDi3/6hC3RVZTujSnzesALObhUrMRVRAhkRwZr8fafeqd/I+oVlCy5AbglpBO2HPLXgRfqlKctXh+ux+tSjUS+9zhbd6qPFybICkjL3Oc6HgmDwBlqPntRJr31ZHPX4YtcCd8fdKshwSywtO/hXYk4Mr9jweV5ITxzAWu1O+0RXoLrUUHZ+e+TlyNEcqGzM10pGekjNkfkxDfiO7Qix379LNNyF1z8ljfPA1VEdfeJ7aW19Xg9FOm0P+Nnuhe6Ew1dVhWswU1YSB5QqutyZOXOV9uwilIviwLgfzB0/bWBDMJlehdHTg1PMgVbPnun++CXPizunR5KnC1U9jjNmd/vp2sq7dL+SdHG+63mAqtD+ni9X9OwmDt3teLcg/RnuIiK9vgGXxH/StzgVEXDaSZVyoEU0O1BxIOp+TTkpoQaqhe8HjjUAk5VLSuOWN9jOJMap6nI/QHWogFjPssBvEPLH/NaFb4foPCKGrdpMgyeHBZHgC9POSQOkJdSSmiD6Sj1+Lq3zyMlPEPRtRHlbpdsSFWo7aKKy7u5KRRl1x0auJKXuz1M1eHYulEqj4k/AOKJrjK5BcK+H1dAlmBuoA/BUOPk8UBBz3NMn4rqkroEav+m0i/QnEjUJckwbRSieYKu09IzMnwTDxmmtnnGoZNqSQpQlYz8Oq9ZD1oQsf8d+pWKJ7TBkCj/uY1LJqDNyNGaU8vGEsjQ3jwW5g54jxzav18yEdzNu5DffIfUHg Cek9sEBC tMxfNFeoKLWaywFbnu5BH//1WOTRmAbH6XMEZKqf6aOvOF/3kBxUiTxg7Qe7PzwAOwjMZ3GGZR50rexCuUn0IQQZpre9MQ6Vwxjb1/P9XuT18PfXwgoR03LO9/WM7+ZuT4uAX9j2Olx6W8r2LhjMX8plTvO9UpIGMSYgd/dAmOo6bSyPkpypnl3bgusw5Lkq6SE1AUgEdgEEKyIIKX7UGFhmvlHxvI0K/+JhmTdhX13B3tz9zAjU2T3eWk5cqO+EVhM69iWo6cVugWpcNc+R4QqZxyaMaNBDrgQ+WoxbdHAITh1uk3OrfUGHazfeQeqHllQ6JPE7DJWZqTr1sCzpGj6yyo1nYeDymcn7flXu/46a8wBz2Tg0SiPh/S+3hOM/cWAsm9kZzWWndvPa9i6EP7DfJXIDEFUZpVkI5CEvUprtB/hA= 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: 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+CogFd4aXrThr2gsiS4g@mail.gmail.com/ Signed-off-by: Bhupesh --- 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 6aa79e2d799c..dfc20fbe389c 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