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Thu, 15 Jan 2026 23:26:10 -0700 Received: from mtkmbs11n2.mediatek.inc (172.21.101.187) by MTKMBS09N1.mediatek.inc (172.21.101.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Fri, 16 Jan 2026 14:26:07 +0800 Received: from mtksitap99.mediatek.inc (10.233.130.16) by mtkmbs11n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.2562.29 via Frontend Transport; Fri, 16 Jan 2026 14:26:07 +0800 From: To: , , , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Matthias Brugger , AngeloGioacchino Del Regno CC: , , , , , , , , Subject: [PATCH v2 1/1] mm, swap: Restore swap_space attr aviod krn panic Date: Fri, 16 Jan 2026 14:25:00 +0800 Message-ID: <20260116062535.306453-2-robin.kuo@mediatek.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20260116062535.306453-1-robin.kuo@mediatek.com> References: <20260116062535.306453-1-robin.kuo@mediatek.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Rspamd-Queue-Id: 455EC1C0002 X-Rspamd-Server: rspam06 X-Stat-Signature: w7bt5aehken9muwqz9zddxwumgrwppnn X-Rspam-User: X-HE-Tag: 1768544777-88356 X-HE-Meta: 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 z9dfILtV /3XJjnnEDWrZCqgV/1QbTcpGEzP4+LZ4WFJ0r7Zi3MgMdPAIFEW17RQHDVNsWaYKceOkIrzDO+9O2jge2O/jxtBausfKR+ZUjcsgo2ZwWD1WCtp9MaoWh6DLgjCc/hCmuHIJS8BGyg4WagHdS2E6P/x9FEEVjK+64exKU9DZLmiPmXx5ZXheEzRcpYDn7GgwPDb7AIAj3PG93rxf7Ds8UIeAa3rZsOFjUH3HDADAQfu7DZWWcCAlQ76xeZn+tOv662729eCzDVAXgnYaNeYlPYv/ElXQEZmF1N1KXI1YZusmLCED4HgRIQMmjgjTY7U+SmXh4 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: "robin.kuo" commit 8b47299a411a ("mm, swap: mark swap address space ro and add context debug check") made the swap address space read-only. It may lead to kernel panic if arch_prepare_to_swap returns a failure under heavy memory pressure as follows, el1_abort+0x40/0x64 el1h_64_sync_handler+0x48/0xcc el1h_64_sync+0x84/0x88 errseq_set+0x4c/0xb8 (P) __filemap_set_wb_err+0x20/0xd0 shrink_folio_list+0xc20/0x11cc evict_folios+0x1520/0x1be4 try_to_shrink_lruvec+0x27c/0x3dc shrink_one+0x9c/0x228 shrink_node+0xb3c/0xeac do_try_to_free_pages+0x170/0x4f0 try_to_free_pages+0x334/0x534 __alloc_pages_direct_reclaim+0x90/0x158 __alloc_pages_slowpath+0x334/0x588 __alloc_frozen_pages_noprof+0x224/0x2fc __folio_alloc_noprof+0x14/0x64 vma_alloc_zeroed_movable_folio+0x34/0x44 do_pte_missing+0xad4/0x1040 handle_mm_fault+0x4a4/0x790 do_page_fault+0x288/0x5f8 do_translation_fault+0x38/0x54 do_mem_abort+0x54/0xa8 Restore swap address space as not ro to avoid the panic. Signed-off-by: robin.kuo --- mm/swap.h | 2 +- mm/swap_state.c | 3 +-- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/swap.h b/mm/swap.h index d034c13d8dd2..1bd466da3039 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -198,7 +198,7 @@ int swap_writeout(struct folio *folio, struct swap_iocb **swap_plug); void __swap_writepage(struct folio *folio, struct swap_iocb **swap_plug); /* linux/mm/swap_state.c */ -extern struct address_space swap_space __ro_after_init; +extern struct address_space swap_space __read_mostly; static inline struct address_space *swap_address_space(swp_entry_t entry) { return &swap_space; diff --git a/mm/swap_state.c b/mm/swap_state.c index 5f97c6ae70a2..44d228982521 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -37,8 +37,7 @@ static const struct address_space_operations swap_aops = { #endif }; -/* Set swap_space as read only as swap cache is handled by swap table */ -struct address_space swap_space __ro_after_init = { +struct address_space swap_space __read_mostly = { .a_ops = &swap_aops, }; -- 2.45.2