From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f47.google.com (mail-ot1-f47.google.com [209.85.210.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B1AA1449EB7 for ; Mon, 11 May 2026 17:18:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778519896; cv=none; b=fDoabHrduVIam2qBqt41ArlB8BCu3iI/9SsXnmFwE8Mwl/UzumOwmjgewFnkyoR4h6d4CzEFBEwP9xrbNh/OZwAV09l9roWA3XZeMWjhVpfh/5+PAul3eA3h7Nn5f4D07ZW0E7hphVX/zR6Hgei2Jk8d9laXrZquW2qJr2O2E1Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778519896; c=relaxed/simple; bh=z3kOpY9ViUaUyJU3gdXhJD52Ymct6W+YUbAiOGuCXgg=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=HG9YoSEmiLpkfpM2Ri2rb3XhypTed5Oug/1Xazr7uHKLf5CemGWsYsLqtNJHkuWJoCQFDECgsPJP+TJGuuEDMlPaGwW7kgXlYtL3QSpONFIrg6qSA5IZRU80HGwA/KWi3DqWzhmD8J2+rPRPY9ehu0FsVTnb6i1UALMsCq6o/kw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=PPVmXizX; arc=none smtp.client-ip=209.85.210.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PPVmXizX" Received: by mail-ot1-f47.google.com with SMTP id 46e09a7af769-7dcdd23fcdfso2455717a34.3 for ; Mon, 11 May 2026 10:18:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778519894; x=1779124694; darn=lists.linux.dev; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-transfer-encoding:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=2PJULk4XF26NffsCR/AJr8MgFQb7EUc2SMqGgA5Onac=; b=PPVmXizX8Wytu86Hp8Z3xgdoSRje1I2vj1OCOU0yXOBRcTOJjGTfm01hFtIWgP8eoE cjQ/EKZib3jnHI+VP+IjQSf4qTa+l1mWQTxSYdozMzHS1lcKwxA/IVgPlaGLy2khGS09 gyniscfJupgBUwrMoxxxLgjPCiPZZv2centEBx6eMFo4OAi7sXX1mM4Y7hGN2HDFy7Ox 5NcP07kIOUGjjkiprClPxFdzGORcIQqafH1T7t0X/MATlBQEz25YW9H6LA7uiqhyb0vp qsfh0PtZfLRCcGRuu77jXLARj2yA046pTnlY1FQ74I9zB4+Vlmc9mWs9FU3YfGICj9mX TBaw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778519894; x=1779124694; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-transfer-encoding:mime-version:x-gm-gg:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=2PJULk4XF26NffsCR/AJr8MgFQb7EUc2SMqGgA5Onac=; b=fy0AUNqCIjHgE/TbpiHZD4dAORi/KfzpQhRZn8pQsv8eU5idbWXIOjJbFygz6Nex5j vGFjpWeJ4K6giOnYVFn0z49X1YebEkmqVjncuuCozQHr+0TAYj23nTk9acXdptvDhVbL 2g+ltjPrbCl5sEPPT7m9rdJWO/9vczm4sMYwIvBE7a5jA38KZUa6pwFSSXK0Z4dFXe/b LMy5tc0SN2MUfgfBgNM6jUz1fuGmTaAIzyraeGEDp/HMVDhjL4/fBGhlYFdFUOqeoLsc x4rlh596w9mBuJLZZhegBWXnuXyLb2gtLwOQc4ObYzSNIL/UnaHNf9DmSGCBp7IvEnG5 4+MQ== X-Gm-Message-State: AOJu0YwaMb2WIaohn0Sm6mLCFYSsKvr3/e8Sv/UYTLaR7vI57gGTsCqt LEqErvZDTg3Y8fPP+akwlWeb2kSiN43GvffUvBs5Nzwtd8wMpn6iQnnH X-Gm-Gg: Acq92OE9R9AKo5z33MOVkRe8HRxaV/au9gzpGecw+IvSFDGZoiKVoV6f5Yv6Samhh41 JSv5PLGOYKGS57tVKyS0mEGTzs1jzw44oLlV88UYqwyexV2yP/aG4gtrGYjNYXODtxdGrvdsYJi XYmLqLPAFEjpullORBgif3q6q28ftFj7M2tWcAxFUqjldtZGvByE2Y8PUXUt1nvKwcYV1plqzP7 mDiol9jgKRgMANPnzmsfFuQjrXPh3AYMQkmd+7jfRBLcALULfY1Qk/m2WaAAMK/urHu7Wy6DJUA Af+MPzaTniVOpG41Y5XDDEntHG/SHswUNkGPMsS5O3Wq0R9L6K4CD3K2C4b4EBFyfh+HiFpgsP2 aQ1r6LoybFHzRoT7j940AnIMJtTuVm8nZD3sc5M6Uq+TpDV5jXHkaEszbebW5ItAEavuggIfmFN /xLSSO+EUdFhSuOPYoBzadYHVYgIR8jHRkmDgORE5YYej9k78I9Hb7r6v7x2wFwoAB9LjW/85wp anwHpUz3aLxuq9Q2g== X-Received: by 2002:a05:6820:161f:b0:696:1860:8baf with SMTP id 006d021491bc7-69998cc094bmr12581594eaf.20.1778519894549; Mon, 11 May 2026 10:18:14 -0700 (PDT) Received: from localhost ([2a03:2880:10ff:48::]) by smtp.gmail.com with ESMTPSA id 006d021491bc7-69b25c9a23fsm6023546eaf.7.2026.05.11.10.18.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 May 2026 10:18:14 -0700 (PDT) Precedence: bulk X-Mailing-List: sashiko@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Mon, 11 May 2026 10:18:13 -0700 Message-Id: Cc: , "bpf" Subject: Re: [bpf-next v3 1/2] bpf: Offload kptr destructors that run from NMI From: "Alexei Starovoitov" To: "Justin Suess" X-Mailer: aerc References: <20260507175453.1140400-2-utilityemal77@gmail.com> <20260507234520.646C4C2BCB2@smtp.kernel.org> In-Reply-To: On Mon May 11, 2026 at 9:38 AM PDT, Justin Suess wrote: > [ 21.604660] Call Trace: > [ 21.604662] > [ 21.604663] dump_stack_lvl+0x5d/0x80 > [ 21.604666] print_usage_bug.part.0+0x22b/0x2c0 > [ 21.604669] lock_acquire+0x295/0x2e0 > [ 21.604671] ? terminate_walk+0x33/0x160 > [ 21.604674] ? __call_rcu_common.constprop.0+0x309/0x730 > [ 21.604679] _raw_spin_lock+0x30/0x40 > [ 21.604680] ? __call_rcu_common.constprop.0+0x309/0x730 > [ 21.604682] __call_rcu_common.constprop.0+0x309/0x730 > [ 21.604686] bpf_obj_free_fields+0x118/0x250 > [ 21.604691] free_htab_elem+0x85/0xd0 > [ 21.604694] htab_map_delete_elem+0x168/0x230 > [ 21.604698] bpf_prog_f6a7136050cb5431_clear_task_kptrs_from_nmi+0xe= b/0x144 > [ 21.604700] bpf_trace_run3+0x126/0x430 that's better. Looks like we moved bpf_obj_free_fields() into htab_mem_dtor(), but left check_and_free_fields() in free_htab_elem(). I think the fix is to remove check_and_free_fields() from ma path in free_h= tab_elem() and fallback to bpf_mem_alloc at map create time when map has kptrs with dtors. Even when BPF_F_NO_PREALLOC is not specified. Kumar, thoughts?