From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (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 3521E445AF2 for ; Thu, 13 Aug 2026 10:02:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786615375; cv=none; b=rEbRgyaBVrs9lAftOvXeDNxDHol4gqVPqdlmuazOPgeIUIdRxZ0ZpIACAEKAXCaWBOc9ddu/R0OTZiBV4KBsbBbsiLZHHeZLwCn5pjQ5TdIul9E6JiQh276K8MvoSaGOu4Tya4j+Yk6n0rZBgOundiyM+cS2gd9F5/B7WHwO1+k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786615375; c=relaxed/simple; bh=SmrcYFoWWX0gEHdUAwCRGijyGvjB/SH6IwdV5jR8akM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=gVs+5UkNBc+4nNZS+yxCQcNcEL1wkDJ5lywMHPkWYtK+XzR7JFVDOwPmpRNCe1qcAG31eFfHW1Y2KxlHoFFld6nci7xhAEWWJmGhntY9U65hYqerUnxOBr4rOcUBc4czUhhRHLRYsXY2T84M/BQl7poFL/40cvsAdUhGV7Ys++s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=jTcssKBz; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="jTcssKBz" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:Cc:To:In-Reply-To:References: Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description; bh=hLVa+zjcHZ3q89ZlAQukI32EVVr5AUEVuCmPcq6Ui6I=; b=jTcssKBz7dr2qg6m1N2so6N7BO q+nPfb1dlbVYlKRSKu278fmNllB8oizjDynyYTea4w/doHRjyyXoc01tCXBbzMNzkh1JL4dvigoq0 wn9U2D9nX1DLlpojcc42pkcjK8uC7zUBZKdBDy6H+OVisKC7JoxPpivwFy1w43r3Fk+lACgIvKg7E m3ECEyRimVWkUTSTq+O4c9spEhe2aBFtGDlmwH1hdhDB4kzZdgVCNM9kcRk9jdvnUSoyyMNfJsNak tSVQZ8+RiYbWt+OpJnF5RVl3Jj2POahrdBK1QLsj+OqgtPFSwUJWJrT7mfV7iUqwSodyCfTnm0rnd LUAj5VuQ==; Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1wuSGv-00520o-3D; Thu, 13 Aug 2026 10:02:50 +0000 From: Breno Leitao Date: Thu, 13 Aug 2026 03:02:22 -0700 Subject: [PATCH v2 3/3] mm: fail the fault on a malformed swap entry instead of retrying it Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260813-swap-v2-3-4a625ccabdae@debian.org> References: <20260813-swap-v2-0-4a625ccabdae@debian.org> In-Reply-To: <20260813-swap-v2-0-4a625ccabdae@debian.org> To: Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , Hugh Dickins , Baolin Wang , Peter Xu , Johannes Weiner , Yosry Ahmed , Chengming Zhou Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, Breno Leitao X-Mailer: b4 0.16-dev-f8e9d X-Developer-Signature: v=1; a=openpgp-sha256; l=951; i=leitao@debian.org; h=from:subject:message-id; bh=SmrcYFoWWX0gEHdUAwCRGijyGvjB/SH6IwdV5jR8akM=; b=owEBbQKS/ZANAwAIATWjk5/8eHdtAcsmYgBqfZYw9iNKkPP+i+19qL3SClZWK1+Fa9721SNcr UBC7tBWG3uJAjMEAAEIAB0WIQSshTmm6PRnAspKQ5s1o5Of/Hh3bQUCan2WMAAKCRA1o5Of/Hh3 bad1EACgMQM2KbtrxWEgwHNbB7QPz+gCJwzh4OW8BQ7Wj+BguF4gu28JGQl1Qy5o9MOFuhNjA4k 7SoINP180rTa9PmSoDVXIflJ+UJbZigq1nsXuJCutdNPOOWM3lPbvAtmhBLOua15cSbKZwRmQsM qf2yCRJwA2nSTAoSWlG86gv4q99tPro36mUr+P/0YWpydC4jXp03XFoExMBal3N/PcAlzUgTpNX EAjZUYc6eBXFOHCYw4A3pf8Bx1MU+0m4b1Yg17k6I3sp2Zi3s7An054zKYiJxzSRmpjgiwAS3m0 YlW4aQd8Zrno/YGyanJjm+1tgNG9KoA4ZHd9gICzh4JvZWsw87FRzlLukpgG+cT/teIEuLRRYIB QrGNs0aaHkuTIihG2ll+ClCEPOCvmmP03po5iAhNuff7YpHYumm25pLw6MU5ZggAWyVYZkwFXqe zmPiUL81D6EGsRC7TVQuXdKChdXupd+5JVn8QNKLuskCdDI1vz8M1Ky/LMd60ryIVTBav/ou1pa 4OIErsleCnefOj0fJqGD0OmnN1v46fePOyhg3qGxJWXTRhEPTcgFXmOWI/yEbjdIG909TFjpebH wdD8R8MdHsJK3jaUakVsRZf7FQGylfaAxTijrZmn//T49hT88BVfT/hYD9al0ZOJZ3teBRYUnwf po/eNDPaRnDsDgA== X-Developer-Key: i=leitao@debian.org; a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao do_swap_page() returns 0 when get_swap_device() fails, which the fault handler reads as "handled". For an entry that can never become valid the retry takes the same fault again, so the thread spins forever, retrying on the same fault. Return VM_FAULT_SIGBUS (Bad access) for a malformed entry (pr_err() was called at get_swap_device()). Signed-off-by: Breno Leitao --- mm/memory.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index 7201e848129a7..fa2b3d2ad3202 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4957,6 +4957,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) /* Prevent swapoff from happening to us, and reject a bad entry. */ si = get_swap_device(entry); if (IS_ERR_OR_NULL(si)) { + /* A malformed entry never becomes valid, so don't retry it. */ + if (IS_ERR(si)) + ret = VM_FAULT_SIGBUS; si = NULL; goto out; } -- 2.53.0-Meta