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Sun, 01 Feb 2026 13:12:38 -0800 (PST) Received: from krava ([176.74.159.170]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-435e10ee04csm39225222f8f.12.2026.02.01.13.12.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Feb 2026 13:12:37 -0800 (PST) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Sun, 1 Feb 2026 22:12:36 +0100 To: Alexei Starovoitov Cc: bpf , Steven Rostedt Subject: Re: memory leaks of ftrace_hash Message-ID: References: Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Jan 30, 2026 at 07:50:13PM -0800, Alexei Starovoitov wrote: > Hi Jiri, > > I see a lot of: > unreferenced object 0xff1100012c967540 (size 32): > comm "test_progs", pid 2052, jiffies 4294681345 > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 b8 be 65 06 01 00 11 ff ..........e..... > 74 3f 5b 83 ff ff ff ff 80 0d 01 a0 ff ff ff ff t?[............. > backtrace (crc 8dddf0a9): > __kmalloc_cache_noprof+0x3a5/0x520 > add_ftrace_hash_entry_direct+0x4a/0x2e0 > alloc_and_copy_ftrace_hash+0x15a/0x280 > hash_sub+0x3a/0x470 > update_ftrace_direct_del+0x349/0x7d0 > bpf_trampoline_update+0xa9c/0x1070 > bpf_trampoline_unlink_prog+0x287/0x600 > bpf_tracing_link_release+0x5f/0x100 > bpf_link_free+0xca/0x300 > bpf_link_release+0x48/0x60 > __fput+0x2fc/0x9d0 > fput_close_sync+0xcd/0x170 > __x64_sys_close+0x7d/0xd0 > do_syscall_64+0x46/0xfc0 > entry_SYSCALL_64_after_hwframe+0x4b/0x53 > > just running the latest bpf-next. > > I suspect it's due to your recent changes in the area. > > Pls take a look. hi, argh.. I had kmemleak disabled due to small CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE looks like change below fixes it, I'll send a patch thanks, jirka --- diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 8574932e66b6..b12dbd93ae1c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6537,6 +6537,7 @@ int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) /* free the new_direct_functions */ old_direct_functions = new_direct_functions; } else { + old_direct_functions = direct_functions; rcu_assign_pointer(direct_functions, new_direct_functions); }