From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj2-f41.google.com (mail-pj2-f41.google.com [74.125.227.169]) (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 36FE925392A for ; Tue, 29 Sep 2026 06:09:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.227.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790662189; cv=none; b=l1xAAspwG/uFoAWNXG2qv3CfVh943TiAOyp5wDAp7V5veGFiGdEU/TDMCh0gNsS7MPy8vtQfHLsMDo+2jGAfyuZtQrS7RZPJruzg9Oi5z9bKOtNVTqJ/qjEdaa3ZMUogDsq/lr5t7QgEEgp8aqOJ2Ywzl8trJygnky/5QBWXcm8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790662189; c=relaxed/simple; bh=kZWWt0EAbhwxvZLPqdZFstn76wKJyVJU2ugalDWAaRo=; h=Content-Type:Date:Message-Id:Cc:Subject:From:To:In-Reply-To: References:MIME-Version; b=OsKP9/YspwLJu5OVvAidjs30GdzA33L+ltam1BP/HqwgvP1hANmZrQWppN/jd+iHFHynLMj6Xz09W0dVn60xwBwAXqBpkRwNwNoztbU/NbLnjShpoX2KwLpaKRl6xPmlvK3e9GuBr3jmbXFk2c55iQxcthigPZK+/crsJOlH7vM= 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=nq1EemL+; arc=none smtp.client-ip=74.125.227.169 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="nq1EemL+" Received: by mail-pj2-f41.google.com with SMTP id d9443c01a7336-2df9754484aso18443855ad.0 for ; Mon, 28 Sep 2026 23:09:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1790662187; x=1791266987; darn=vger.kernel.org; h=mime-version:content-transfer-encoding:references:in-reply-to:to :from:subject:cc:message-id:date:content-type:from:to:cc:subject :date:message-id:reply-to:content-type; bh=kZWWt0EAbhwxvZLPqdZFstn76wKJyVJU2ugalDWAaRo=; b=nq1EemL+ii657ovvniP7Iy68oWbN7pZB3bCGtzJ0RcttWCb2s5VcBCir8ZGzV4SldT q0KYZET16lnI0SWrIENK1zk4kVMOLt4iNvFksEc6wOGQ0jb4mf67SCQqvccXWbdL/bxU mSuXc2QRPiGrtNFPoybj1uHUCOS4c+STT9GWA5m1vlNNEzmDrnfBQ5NDcuXdcHBK+qri lYcAYyYPdYNOyWr30i7ghwYgeoHOPTaaDqLUFEtv//reuaMtnpAUREanshTVZBqLgeJD LWgYIvS/BE0iG80HC7YEXk4gBwOETCasDcIM1L2vRwJSEnZzApMFXOLG0vyKxSu0RksA myoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790662187; x=1791266987; h=mime-version:content-transfer-encoding:references:in-reply-to:to :from:subject:cc:message-id:date:content-type:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=kZWWt0EAbhwxvZLPqdZFstn76wKJyVJU2ugalDWAaRo=; b=tXX8cDslSsZNDqOLIQp8GzskuATxUISiUtqybWo1Jzj1ZFsazitEcJbqdvJ7tiY4kl w6bJaaPuuh0MNsjNTxuHuIkmwW/JqawlN5XjcB+QwJPd3j7M0u2d7viUpVuANytUIfIq j+sxU6H6PYBexiJYQKWaTY8S1vx7ZOHe8QlSrd5gbXH/E3mCf77gJlEPbFdJdSke6koA WbDfcgsL6XI03Sz0TWviZIBkYV3QA26rqikWc+7XCJfibkT1KzfQvoEGTPPkoSA2UYeZ ebz/z72bI3U6YXwZ1sJrJuJZncPMdTGCtqaEdSsyVVtrA0zVJ89IRcPuRbURiBrgrh12 v9CQ== X-Forwarded-Encrypted: i=1; AKwUvBy3y2HNvtGQ557hBZBRgSj9utTvmTT3noBKLePbEmtfWYG3HA6wQNr1GRS0pqp3rla2XPeBG7P0t3uttm4=@vger.kernel.org X-Gm-Message-State: AFq9FYK2f6HWELI0uhPUYwdVHZ/wMHgq+lEJd0flgJ5id2td59ks6RhU kVCqcfiInRHJH7oF3KAhqbSqIbjgR2vztbNQreZ0xqFgvLIbPZVMxd5I X-Gm-Gg: AYBFou2rtgrSOw6hcJto313o7ZOul2xf8zdwF3a5NXM7QIuV3YUdVsMNaUBqOt6cQ/a yPMddkjX3sBUv/a+iIpG4n+L1SC40lPs77mq+37TTN/mS0g3x0Da1txaYHyIZk7qI2W/7tMXA/c ye21lXQ1jAM3mDiZ9l1NoIuN+a7MvIboMdChhJz4OeNXvIjvKV8cZgXGQARaaAUCLfS2quTC4Er RoCBLZlAZ5jD7SGvSww3UYlZvMLve2puzsDrckFr+JScQSxvKNQs2OftusqL7GWUN6J22e00PRH 05ga58SL08rMfiQlM7gwUoB6jC0WCLz+HpYruKcKXExkTYE3GE5HX2LlB2Wdfr/h8f4GNVPfm4i nvuDL3fdtG0sU4IL1vVUORAfgYOTeG+ABDC86nYsl8sG/G/uvyySFok1fhOCFdWRSybgKMooggq Kfm1OSZhIPoYjSWBP/vWnAHks+l8fMEjbHKYj7VF+jpj3FZezh3FsMPoxpgf1fTLNklxqQqF6AR 3q774LoKV1G9cR8uJEG+ARcvvL0AHMz3hg4oTJPdnoCjzW0IU3AP7TqJIQyOdmwBSuEl5lJLZXK s58= X-Received: by 2002:a17:903:2f50:b0:2dd:c0ff:e72a with SMTP id d9443c01a7336-2df7dff64ffmr113965515ad.60.1790662187466; Mon, 28 Sep 2026 23:09:47 -0700 (PDT) Received: from localhost ([153.61.198.253]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2df9142b00dsm50889685ad.49.2026.09.28.23.09.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 28 Sep 2026 23:09:45 -0700 (PDT) Content-Type: text/plain; charset=UTF-8 Date: Tue, 29 Sep 2026 06:09:44 +0000 Message-Id: Cc: , , , , , , , , , , , , Subject: Re: [PATCH bpf] bpf: Fix smp_processor_id() warning in rhtab_delete_elem() From: "Alexei Starovoitov" To: =?utf-8?q?=C3=96mer_Mete_Kaya?= , In-Reply-To: <20260928173703.504474-1-omermetekaya0@gmail.com> References: <20260928173703.504474-1-omermetekaya0@gmail.com> X-Mailer: mkdraft (claude review draft; edit before sending) Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, Sep 28, 2026 at 08:31 PM Ömer Mete Kaya wrote: > bpf_mem_cache_free_rcu() uses this_cpu_ptr() which requires preemption > to be disabled. In rhtab_delete_elem(), this call happens after > bpf_enable_instrumentation(), so preemption is re-enabled at that > point and this_cpu_ptr() triggers: bpf_disable_instrumentation() doesn't disable preemption. It's migrate_disable() plus bpf_prog_active++. bpf_mem_alloc relies on the callers to disable migration. See the comment above bpf_mem_alloc(). All callers of rhtab_delete_elem() do that except __rhtab_map_lookup_and_delete_batch(). That's the bug. bpf_disable_instrumentation() in rhtab_delete_elem() protects the bucket lock from NMI progs. rhtab_map_update_elem() calls bpf_mem_cache_alloc/free() outside of it too. Don't stretch it. Disable migration in the batch. > Fixes: 6905f8601298 ("bpf: Allow special fields in resizable hashtab") Wrong tag. The batch came in commit 818e00848227 ("bpf: Implement iteration ops for resizable hashtab") pw-bot: cr