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Thu, 15 Jan 2026 08:14:15 +0800 Received: from mtksitap99.mediatek.inc (10.233.130.16) by mtkmbs13n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.2562.29 via Frontend Transport; Thu, 15 Jan 2026 08:14:15 +0800 From: To: , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Matthias Brugger , AngeloGioacchino Del Regno CC: , , , , , , , , , Subject: [PATCH 1/1] Restore swap_space attr aviod krn panic Date: Thu, 15 Jan 2026 08:13:43 +0800 Message-ID: <20260115001405.3513440-1-robin.kuo@mediatek.com> X-Mailer: git-send-email 2.45.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Rspamd-Queue-Id: 32FF180002 X-Stat-Signature: pqu8tw3zdnu48h3fg64af8qojwf6c9km X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1768436063-453220 X-HE-Meta: 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 bBpFxFSc GrPaRA5zD0TCxXif7nTlmszdF9LjjzkcXzJRKbThACgGAOmfkQ1fIQKP8jSdmPM6roY8A+ZbhVYPel3Kn/eTneyCkdxJ01GD5xLQRJkZgxXWT6MWJSw+t+nr7ZlV4AaMbRJHsQhpjBMn59zQRBc7CF4AHoXVzVYsJmCCoNJAggfT8ddrOGn/oo4eafd6oH0Z/vN3dNtd1lfkaB2pwj7JUmnor6JHqgtxOcLXS/N8Flkv/tb0EdFvc3Tm5FGl0uI9HnCXevIgrHw3aPk68yrfgfrw8TrbvpTWCBVDq6/biV2EjAGA+oX3/kYvhw8lShRdnhdwq 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" Restore swap_space attr avoid krn panic 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