From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 663A8606A31A for ; Sat, 31 Oct 2026 09:42:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=MRMlhKX5 Received: by kanga.kvack.org (Postfix) id 6FF076B05BD; Sat, 31 Oct 2026 05:42:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6D4D86B05BE; Sat, 31 Oct 2026 05:42:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5C48B6B05C1; Sat, 31 Oct 2026 05:42:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 27F6A6B05BD for ; Sat, 31 Oct 2026 05:42:23 -0400 (EDT) Received: from smtpin08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 42AF0A859A for ; Sat, 31 Oct 2026 09:42:22 +0000 (UTC) X-FDA: 85382430924.08.1A01AF7 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf07.hostedemail.com (Postfix) with ESMTP id 8B14340006 for ; Sat, 31 Oct 2026 09:42:20 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=MRMlhKX5; spf=pass (imf07.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793439740; b=r3U5Q8msGSba+QKqZ7cUNwW19quaYCT3+K2T2B86dhL/94PjRqv+on1mfVN11b0GvAwSs6 +FGjp/W/XNsKcPkg3sUN7wZuowlcWvol7o70YZytqIt07pX7cU1fBq1bDvjjMOMNn5ht4e 8q1yLGiRN+m2Voisgdq2KTOHEwkuOI4= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=MRMlhKX5; spf=pass (imf07.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793439740; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=CIQELR659Q9Tf/3uwyZF+FBJ9ojsDWRhmuf6iagVj0E=; b=eSGC8kTmxnwPo3j6BinyCHe+XRQ9Curj5/bV5mCiOnkpWkcsEpQD9QO54V+7iN8z0UTz4d cbezQ70Q27nRz0sQzj+yCP7bRgXU30EITUiDIjqBzjMOd8dNZMd9LKH6KVKbK2RsPm/PjC qWEN9sjISa3AcaKK3SPWjxOHrp0XTPY= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 1F2FA600C8; Sat, 31 Oct 2026 09:42:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD04B1F00919; Sat, 31 Oct 2026 09:42:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793439739; bh=CIQELR659Q9Tf/3uwyZF+FBJ9ojsDWRhmuf6iagVj0E=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=MRMlhKX5yYtu9Zu1TIoDkRBx6SKZ77pEsqYPoGWttWMJ789xLuskCTAEOHqJOJjK5 RzdNIM06+bIZ8ucQfJiba1rtB+ygtl4RpPvBNUGW8+OqH7db7KnS/Xh+NhRAceixnr Hllht5oMWUQbmnzHBqQOgXVy2DHi7TUe7BPA2VLRKwiTCqR98M6YBJilNAFUhWZ2BR oWA18ApNVRD15Vz4alM9A15A+UxrdFEGnaeEA9nsPJipiLfQ65pUp5sd7MnyR7XMvg I0w9rpePXECj6FXlcAjS5Aayn6NFP8ciD3KQhSySn1eaCEPkz6ykj+FfCNCvMpRlRh kr+/KKjMUexCA== From: "David Hildenbrand (Arm)" Date: Sat, 31 Oct 2026 10:39:37 +0100 Subject: [PATCH v3 08/47] mm/filemap: finish fault cleanup before dropping the fault lock X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261031-fixes_core-v3-8-d6437171ecc3@kernel.org> References: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> In-Reply-To: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> To: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, stable@vger.kernel.org, Chris Mason , Thadeu Lima de Souza Cascardo , Muhammad Usama Anjum , "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4136; i=david@kernel.org; h=from:subject:message-id; bh=jVrwzE4M+fmc5d2w4GN18QrhLHyd8aSra6LYB2SIrA4=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLKebk+b+6H3hOLR81MWSLv0Hb1lHPeKQ3yn+BWW1bcWx SsFrtW+2lHKwiDGwSArpsgSFHzf4OXLdbXVbnzMMHNYmUCGMHBxCsBEHlxjZFhw5bPZdF2D6YK9 mk13VwVUGl+P4ZQNmdc6o1XNLHgH33JGhpuBCUeajn/PNOkO2lFuk8DzyDPmUE3P9m0XVR+/zPn SyAAA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspam-User: X-Rspamd-Queue-Id: 8B14340006 X-Stat-Signature: icykugug5yu3nce3u5akakfmqyu7q9o8 X-Rspamd-Server: rspam01 X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-HE-Tag: 1793439740-320863 X-HE-Meta: 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 6XikAJds DbYFDwcwHpDMrxjRRF6XM7KrtUhunh9Wc3UekPvRWXAJV6i0em2PMnSZxH7thVm/NWdJA5QxvMRO1Espx0ZTYvKRwk1RK0S6z4mJdKMP+qgVZ0h1PUHOkhpp0mhD67iD0s7bO0m3qt8wxatl654V2PHmT/cdCsO3F/Y3LINlsGN9bwLHaTrkYvOElIy43DWFYX8XkpsZHgrJz7WoFjC38sFkWf9mP/45TcV7GY8Bc2QcOGSyS6jK+kgzVU57HccB0ZE/O9CBNMuBPwy9RP3R0IwggzrJ8TnHzCB7WQG3Di5n7VRRpXtjYe4OfltjZBiDGf+DawKdZxKeXB3FafBSJuh38yvoAlW/fcFZcCG+3YYKEVfme5pTaLS8zjOI6DSLKkAYSuZF4PamYxPHW/iu5CtpqbwMYiHZ+9sMXJU0/gE6W3Q+oEw9NvPcCGA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On a retried fault, a fatal signal interrupting the folio lock wait makes lock_folio_maybe_drop_mmap() drop the fault lock without pinning the file. However, filemap_fault() may still need to release mapping->invalidate_lock. A concurrent munmap() can release the last file reference and free the mapping before that unlock. Defer dropping the fault lock to filemap_fault()'s retry cleanup, after releasing invalidate_lock. If the fault lock was already dropped for I/O, release the existing file reference instead. Keep the fault lock held for FAULT_FLAG_RETRY_NOWAIT as before. Fixes: 730633f0b7f9 ("mm: Protect operations adding pages to page cache with invalidate_lock") Cc: stable@vger.kernel.org Reported-by: Chris Mason Reviewed-by: Thadeu Lima de Souza Cascardo Tested-by: Muhammad Usama Anjum Signed-off-by: David Hildenbrand (Arm) --- mm/filemap.c | 37 +++++++++++++------------------------ 1 file changed, 13 insertions(+), 24 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 6b5e1d866a9e0..b04be64a5069f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3308,11 +3308,11 @@ loff_t mapping_seek_hole_data(struct address_space *mapping, loff_t start, * @folio - the folio to lock. * @fpin - the pointer to the file we may pin (or is already pinned). * - * This works similar to lock_folio_or_retry in that it can drop the - * mmap_lock. It differs in that it actually returns the folio locked - * if it returns 1 and 0 if it couldn't lock the folio. If we did have - * to drop the mmap_lock then fpin will point to the pinned file and - * needs to be fput()'ed at a later point. + * Returns 1 with the folio locked, or 0 if locking failed. + * + * On both entry and return, a non-NULL *fpin means the fault lock has + * already been dropped and the caller must eventually fput() the file. + * Otherwise the fault lock is still held, including on failure. */ static int lock_folio_maybe_drop_mmap(struct vm_fault *vmf, struct folio *folio, struct file **fpin) @@ -3329,21 +3329,9 @@ static int lock_folio_maybe_drop_mmap(struct vm_fault *vmf, struct folio *folio, return 0; *fpin = maybe_unlock_mmap_for_io(vmf, *fpin); - if (vmf->flags & FAULT_FLAG_KILLABLE) { - if (__folio_lock_killable(folio)) { - /* - * We didn't have the right flags to drop the - * fault lock, but all fault_handlers only check - * for fatal signals if we return VM_FAULT_RETRY, - * so we need to drop the fault lock here and - * return 0 if we don't have a fpin. - */ - if (*fpin == NULL) - release_fault_lock(vmf); - return 0; - } - } else - __folio_lock(folio); + if (vmf->flags & FAULT_FLAG_KILLABLE) + return !__folio_lock_killable(folio); + __folio_lock(folio); return 1; } @@ -3572,7 +3560,7 @@ static vm_fault_t filemap_fault_recheck_pte_none(struct vm_fault *vmf) * vma->vm_mm->mmap_lock must be held on entry. * * If our return value has VM_FAULT_RETRY set, it's because the mmap_lock - * may be dropped before doing I/O or by lock_folio_maybe_drop_mmap(). + * may be dropped before doing I/O or when aborting an interrupted wait. * * If our return value does not have VM_FAULT_RETRY set, the mmap_lock * has not been released. @@ -3728,9 +3716,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) out_retry: /* - * We dropped the mmap_lock, we need to return to the fault handler to - * re-find the vma and come back and find our hopefully still populated - * page. + * With fpin set, the fault lock was already dropped. Otherwise it is + * still held. Release invalidate_lock before dropping either protection. */ if (!IS_ERR(folio)) folio_put(folio); @@ -3738,6 +3725,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) filemap_invalidate_unlock_shared(mapping); if (fpin) fput(fpin); + else if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) + release_fault_lock(vmf); return ret | VM_FAULT_RETRY; } EXPORT_SYMBOL(filemap_fault); -- 2.43.0