From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794408536; b=BjSLEngut+XMfkJ41pJqHsO428hD0xn2H1hU1tN/y55OFk9Wy49pJN5Vd2dETI/YUPUV TqplvwBR0AEIN2AnRclQEH6Dh/5CbDLZoQRF4ku6AdHSL9yxLhaTaAGHDH8ttmeC513vR oU2Bi1D2Q+jAka0foNRufmlgGTpjyfX/7ZHismZnhz7OciRUzxtTtTHp7PNmDxn3yhU/6 2IS1+Q+NLZ7QSsAF/FnZDFUZxGqp1PQPoD+DlnA99qiB29Q35glTio3JruSGEa0NKPgsM rsVYUa5C2kPJDNfDC8Ys1qJSm/7BtAbPwh4bhC1aOvDfQNbQkuKAePXd/Xwmy9l0OWg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794408536; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=0Epdyfueyi/37oyon1G31vg9AvMN1aBFSMT6SN7+dgk=; b=bd3lBWSTCjKy1vDurK1pRR6icLkWnQ2av2ySkCabsEIMW5zoNJV8W22p3Ag7wveLeIli BcW84LiLvrJvcJwCfQO6GNhDToGWFgi+M5oILl4v8I6+f1+0jgB474XGtNAGWl1aYsEFF 9pxF3mssd1Gq3oepvBcH4rNUXtt0Sa5f+pyhuSOCq+rYQfJB9v5R4Aa31VKhNBiSrw67b Ov4mm6Of647nVZ7fwW99paVEmQqIpx6V3FEPGD1TQrRJeKT0ILt23FvWxeYG+DA0+Pr8F RHLLrJA5RasJnka+Xi6hpQ33AGSW1WKvTiTlOfkGxaiLk3G3UvNzOJo2iwEQZau39gQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=QYj25GD8; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6062D606A321 for ; Wed, 11 Nov 2026 14:48:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=QYj25GD8 Received: by smtp.kernel.org (Postfix) with ESMTPSA id A64441F00A05; Wed, 11 Nov 2026 14:48:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794408536; bh=0Epdyfueyi/37oyon1G31vg9AvMN1aBFSMT6SN7+dgk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QYj25GD82lyXFMlrPIY9EOSuCTp7DvK/VV9Vlryz2KpPD1zA81Um8gTXKj6nOI5M6 kL77nWeU2Duat1hr8mNdRkiqpMTlniBdkICdUL0z0wnrN1Qs5zJ3tTfH3csRgfmJlF bgNCnt5S4yQhYskLgd7rjYWvQH7SKmi71kO7D6/7ar6Fe+ova33CutVtJxUlciGdk3 PBsyfy9flY0ilt4eqjMf0u1AnAB4cAM1I8vIbGNs/WIM0kVvpHFIXbs2U1Lo8hiWxD ER/6wLNvgaQ+F0nIbh+1hUsIuTS2ccFeyvsTigUGDwkyV/InRJFn70CbwzUs+dx2Zi PkpGMCqsHt5FQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Chao Yu , stable@kernel.org, Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.18.y] f2fs: fix to invalidate curseg if change_curseg() fails Date: Wed, 11 Nov 2026 09:48:54 -0500 Message-ID: <20261111144803.2438566-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107051114-failed-6.18-e74476ad8162@kernel.org> References: <20261107051114-failed-6.18-e74476ad8162@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chao Yu [ Upstream commit e74476ad8162c1facc74b74ce2d1372492df872e ] Our consistency stress test (fsstress + fio + atomic write workers + "f2fs_io shutdown 1") triggers below kernel BUG: F2FS-fs (vdd): Stopped filesystem due to reason: 0 ------------[ cut here ]------------ kernel BUG at fs/f2fs/segment.c:3989! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI Workqueue: writeback wb_workfn (flush-253:48) RIP: 0010:f2fs_allocate_data_block+0x257a/0x38e0 Call Trace: do_write_block+0x155/0xc10 f2fs_outplace_write_data+0x192/0x340 f2fs_do_write_data_page+0xc57/0x1880 f2fs_write_single_data_page+0xda9/0x15a0 f2fs_write_cache_pages+0x973/0x1f20 __f2fs_write_data_pages+0x6c4/0x1890 do_writepages+0x21e/0x560 __writeback_single_inode+0x119/0x11b0 writeback_sb_inodes+0x67d/0x17a0 wb_writeback+0x207/0x820 wb_workfn+0x128/0xc30 process_one_work+0x925/0x1600 worker_thread+0x60a/0xff0 kthread+0x35f/0x460 ret_from_fork+0x474/0x7e0 ret_from_fork_asm+0x1a/0x30 The BUG is f2fs_bug_on(sbi, curseg->next_blkoff >= BLKS_PER_SEG(sbi)) in f2fs_allocate_data_block(), next_blkoff was 512. The root cause is a race in between atomic write commit and shutdown as below: Thread A (commit atomic write) Thread B (shutdown) Thread C (writeback) - f2fs_ioc_commit_atomic_write - f2fs_commit_atomic_write - __f2fs_commit_atomic_write - __replace_atomic_write_block - f2fs_replace_block - __f2fs_replace_block - f2fs_ioc_shutdown - f2fs_do_shutdown : F2FS_GOING_DOWN_METASYNC - f2fs_sync_fs - f2fs_write_single_data_page : pass f2fs_cp_error() check - f2fs_stop_checkpoint : set CP_ERROR_FLAG - change_curseg - reset_curseg : curseg->segno = new_segno : curseg->alloc_type = SSR : curseg->next_blkoff = __next_free_blkoff() which is BLKS_PER_SEG if there is no free slot in new_segno - f2fs_get_sum_cache : return -EIO due to f2fs_cp_error() : return error w/o restoring curseg : goto out_unlock, skip restoring old segno, blkoff and alloc_type - f2fs_do_write_data_page - f2fs_outplace_write_data - do_write_block - f2fs_allocate_data_block : curseg->segno is valid : f2fs_bug_on(next_blkoff >= BLKS_PER_SEG) Since commit 86f33603f8c5 ("f2fs: handle errors of f2fs_get_meta_page_nofail"), change_curseg() can fail after the curseg has already been switched to the new segment, then the curseg is left in an inconsistent state: it points to a segment which may have no free slot, its summary block is zeroed, and the caller can not restore it. Subsequent block allocation on the curseg will trigger the BUG. Moreover, the writeback thread dies with curseg_lock, curseg_mutex and sentry_lock held, so the commit, shutdown and other I/O threads hang in D state. Since change_curseg() only fails once CP_ERROR_FLAG is set, no checkpoint will be committed afterward, let's invalidate the curseg via reset_curseg_fields() on failure, as new_curseg() does for -ENOSPC, then f2fs_allocate_data_block() will fail with -ENOSPC on the curseg instead of triggering BUG, and do_write_block() can handle the error since CP_ERROR_FLAG has been set. Cc: stable@kernel.org Fixes: 86f33603f8c5 ("f2fs: handle errors of f2fs_get_meta_page_nofail") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim [ sashal: adjusted error-path context to use PTR_ERR(sum_folio) instead of PTR_ERR(entry) ] Signed-off-by: Sasha Levin --- fs/f2fs/segment.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index c0ec2715408e8..1097e688d165f 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -3067,6 +3067,7 @@ static int change_curseg(struct f2fs_sb_info *sbi, int type) if (IS_ERR(sum_folio)) { /* GC won't be able to use stale summary pages by cp_error */ memset(curseg->sum_blk, 0, sbi->sum_entry_size); + reset_curseg_fields(curseg); return PTR_ERR(sum_folio); } sum_node = SUM_BLK_PAGE_ADDR(sbi, sum_folio, new_segno); -- 2.53.0