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 1452660A2637 for ; Thu, 29 Oct 2026 20:35:33 +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=TnPvwTVd Received: by kanga.kvack.org (Postfix) id 268A36B05BE; Thu, 29 Oct 2026 16:35:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 218356B05BF; Thu, 29 Oct 2026 16:35:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 12EA26B05C0; Thu, 29 Oct 2026 16:35:32 -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 CDCA06B05BE for ; Thu, 29 Oct 2026 16:35:31 -0400 (EDT) Received: from smtpin04.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 4ED62A8010 for ; Thu, 29 Oct 2026 20:35:31 +0000 (UTC) X-FDA: 85376819262.04.981A58F Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf30.hostedemail.com (Postfix) with ESMTP id 7AD0B8000A for ; Thu, 29 Oct 2026 20:35:29 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=TnPvwTVd; spf=pass (imf30.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 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=1793306129; 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=JIqz6J3TwNkGVPVANkFEl6jPQa+Zivkvvh5bXw83jC0=; b=MasxkOPhhzZtxAtkYkrqp4af5tHR/fCnQgRfFEJtdE5jgwOG+an1SB8+v/0cyVZyyHPh69 hc+pV3g5AH8tFWNxOEElp2H/rRjdrUQv/hcA4Kd0pSO7rvJzV4z/9mZ1z6stMdJj40VWt0 Q+q6gCL5JttECTLhqYIuq6bWExlzAe4= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793306129; b=llzPhUIbCZOZ0+v3I9X2hqjJD9y6AW8qQ4Fx931OUqCwPZwNpXyUqjbq8Dc0iO/Pk7ZfP6 4vZ/T7A6SE4ifxiqCa+7EbnWn3VNtTJ8s1xol6gPH25cwPcR/w8qUWUkLKWo8EawEUC0W4 5sd44DIZoNypgZ0jhEVp4xptEV7PUNc= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=TnPvwTVd; spf=pass (imf30.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id B257E4095E; Thu, 29 Oct 2026 20:35:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 655ED1F01825; Thu, 29 Oct 2026 20:35:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793306128; bh=JIqz6J3TwNkGVPVANkFEl6jPQa+Zivkvvh5bXw83jC0=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=TnPvwTVdhfq5HQD+vvFOcn8G/MzS9HbLRPmKgokJVWGtdm6ivj0/dhyWASnhrcLiL ZN4i+CpGa5N9kOSCQrMCXDeUbAKZd7alG2BxvMvzAOROCgMDr/lTJTYYaKeE3rrAUR 6KzV1RVU74/NaDc3KZ+6vyUfDSmZIp6PCUP6k4Jo4eTEpk+00SbIdCuq90C0L/1uww 5wrHFXdgPxr05IDgusi0rT9Q93tvtbt4aVHs+6j/ScZMe6mP/IC9VohQbhhalkgC0q lQY7qrUH+AxPdMcuMBp/OivDUp8Joxs/UCz+baxOhtfhMGCpnjd+RB2zjjKYEyxKVa 7Fspe6PVIpRvw== From: "David Hildenbrand (Arm)" Date: Thu, 29 Oct 2026 21:33:03 +0100 Subject: [PATCH v2 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: <20261029-fixes_core-v2-8-a64ce7f83abb@kernel.org> References: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> In-Reply-To: <20261029-fixes_core-v2-0-a64ce7f83abb@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 , "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4079; i=david@kernel.org; h=from:subject:message-id; bh=8upppjNvZx+R13jPGAHHeYmNd3f41Ow9JcPqILGtH6s=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLIer201VjohpJtZeHGJz9T8Nfl1gi+zM/Y0Vf9e1M5z6 8v/jZZ+HaUsDGIcDLJiiixBwfcNXr5cV1vtxscMM4eVCWQIAxenAEwk3ZThf3KrZ4le176Zx1k2 WFlwPoxvjXyys75Zl/v+LDPZu7qBLIwMDUqqbtfWHb9bzv588VNBExGh21FTHmb++uVxMNa+4tw eHgA= X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 7AD0B8000A X-Stat-Signature: 6kjsczzn41ob6wzpikb1n9quzuqyz6g4 X-Rspam-User: 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: 1793306129-921715 X-HE-Meta: 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 6gIUgnE1 n9sDinsCG1477VSeQPhrcsuZ4XdzyrCT8Ps0/PrU8kL7Nv6Rwq8gyxNHvEkNlAZ9mvBJKZvofmxS0sdlNrVw98z6oq3OhhMm+51sm7tmMVz8dV28vU5VZIIobPedc7K/3O6I7KQRjgywFd4A6GUHdfIpVcWg5JMHw1ohpVwbO/FCsKwgpWceQmVwiHU55XCnLFkX1ADrLlRUK9IZAuAM4HiYl2nTcQkn0fAGeJxALRJ9bVHbiIswzqkW5CwJsMrtx5hjClMA9k7bw0/H4Z0QBl9Wedm1dXBAmw/f7u5hNsBfxN5BG5N0PmBADWYuOgCYz6ls8nBgwAMlB1SVh1nbW15g0rLjOMKol+zioFOv0M9Np7E37soIhySeIJ/xyWG7TDD3y 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 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 6b5e1d866a9e..b04be64a5069 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