From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 074583E168A; Mon, 10 Aug 2026 13:49:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.3 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786369764; cv=none; b=JY4VpxOUXkS+swwsHWKM5nWm/D92+5kGOeQ3K71n7GHoaEUJLlz2O0hqozp3O249lCXAbp14amarAp+INHQSnbinUWNtUnKpX9Ts/ZpZ92n7b2bPJ5qEbimeg4qh2/U/KhONuMGNwgN8VxuEcVOEXtQwpronryf7VkNt4MwnVz4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786369764; c=relaxed/simple; bh=Ow+GUhBa0rYrOzu+TOd8Giv7ZdKkyrHqBi7vdrmrpak=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=q6078q5rQEaNFxgV8DEFMbnZ+eIglmhd7OPqUyqLSdqdxOFXG0RolxgNV0D3Hrx/9PKDsLKr7vhUsqeGbl2D3spOpMNG8Kt1dZ/gIIa6nvPZ+zuIRpDbfiwZATU+6GJbUm6zbNDYT3aDNWTlYBhApfUIQsnDHDHSfEnJZx3JAYc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=kpj/rklD; arc=none smtp.client-ip=117.135.210.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="kpj/rklD" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=9Y Og8U53lS/fw3psYdBRrJ5Kb6g8ticHNZVmkoqWgo0=; b=kpj/rklDl1H/PMA4sj bR77oTDdkjXdyTmVX7KFZ1b4LVu294Q7MJKVlAxQFGITlphlop29vw3WILDoxqpe X/00dISTuy82bpDlCbvm8zYGI8pMfgFkeNZL/Lz2mpQZrPCB7BuJ3orhvkMTimXZ qEij/6yoMN7E3R3Bj/cslubqA= Received: from nec8-i7 (unknown []) by gzga-smtp-mtada-g1-4 (Coremail) with SMTP id _____wCnJImg1nlqBKwLPA--.27752S5; Mon, 10 Aug 2026 21:48:23 +0800 (CST) From: chenyuan_fl@163.com To: bpf@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , Yuan Chen Subject: [PATCH bpf-next v3 3/3] bpf, arena: check range_tree_set return in arena_free_pages and arena_free_worker Date: Mon, 10 Aug 2026 21:48:00 +0800 Message-ID: <20260810134800.2875487-4-chenyuan_fl@163.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260810134800.2875487-1-chenyuan_fl@163.com> References: <20260810134800.2875487-1-chenyuan_fl@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wCnJImg1nlqBKwLPA--.27752S5 X-Coremail-Antispam: 1Uf129KBjvJXoWxCrWrCFy7CF17Gr47Xw1rCrg_yoW5Xw1fpF 4UJa9Yyrs5Jw4xAr43GrWv9rn8G39Yqa18G34UK3WrZ34av3srtF48AF1UuFyUGFW8Xr4U KF4UXw1YkrWDZFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07j9pnPUUUUU= X-CM-SenderInfo: xfkh05pxdqswro6rljoofrz/xtbC5gjYlmp51qjLVgAA3Q From: Yuan Chen arena_free_pages() and arena_free_worker() now handle range_tree_set() errors. arena_free_pages() aborts the free on error, and arena_free_worker() moves range_tree_set() before PTE clearing so that a failed tree update leaves the PTEs intact instead of freeing pages that the arena free tree does not track. Also check the range_tree_set() return value in arena_alloc_pages()'s error path, which restores the unpopulated tail of a partially allocated range; log a warning instead of silently leaking the virtual range when the tree update fails. Signed-off-by: Yuan Chen --- kernel/bpf/arena.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c index 555ee2531ef9..d57a0b617525 100644 --- a/kernel/bpf/arena.c +++ b/kernel/bpf/arena.c @@ -766,7 +766,9 @@ static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt bpf_map_memcg_exit(old_memcg, new_memcg); return clear_lo32(arena->user_vm_start) + uaddr32; out: - range_tree_set(&arena->rt, pgoff + mapped, page_cnt - mapped); + if (range_tree_set(&arena->rt, pgoff + mapped, page_cnt - mapped)) + pr_warn_ratelimited("bpf_arena: failed to restore free range %ld+%ld after partial alloc\n", + pgoff + mapped, page_cnt - mapped); raw_res_spin_unlock_irqrestore(&arena->spinlock, flags); if (mapped) { flush_vmap_cache(kern_vm_start + uaddr32, mapped << PAGE_SHIFT); @@ -881,7 +883,12 @@ static void arena_free_pages(struct bpf_arena *arena, long uaddr, long page_cnt, if (ret) goto defer; - range_tree_set(&arena->rt, pgoff, page_cnt); + ret = range_tree_set(&arena->rt, pgoff, page_cnt); + if (ret) { + raw_res_spin_unlock_irqrestore(&arena->spinlock, flags); + bpf_map_memcg_exit(old_memcg, new_memcg); + return; + } init_llist_head(&free_pages); cdata.arena = arena; @@ -1004,11 +1011,18 @@ static void arena_free_worker(struct work_struct *work) kaddr = arena_vm_start + s->uaddr; pgoff = compute_pgoff(arena, s->uaddr); + /* + * Mark the range as free before clearing PTEs so that + * if the range tree update fails we leave the PTEs + * intact, avoiding an unrecoverable state where pages + * are freed but the arena free tree does not track them. + */ + if (range_tree_set(&arena->rt, pgoff, page_cnt)) + continue; + /* clear ptes and collect pages in free_pages llist */ apply_to_existing_page_range(&init_mm, kaddr, page_cnt << PAGE_SHIFT, apply_range_clear_cb, &cdata); - - range_tree_set(&arena->rt, pgoff, page_cnt); } raw_res_spin_unlock_irqrestore(&arena->spinlock, flags); -- 2.54.0