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=1794047687; b=0Ia2qtXKSEGIubRzTJhnTsCJ9dNHavliNGSp0G+a/weVg07dTQGkQhvnmr46NqBfCpYx vizozwp1xTddKeYLK+wJOjZIuN8xfDkn39FDc4zYzdI9cfWJx7qKEamO2VUrhs4971ybV NxC0bWmIpfXc7DO9PLTeqrnJXXlJBfc+BANdooWcNhoemGctNmt6OuNFFOZ7/gp02hlrB 94b0wg/161En6euhECfJlngCQBGFnXkihvVm/p168Ci4h4EXhxMwFrFWVe1LkdlJutmHU PsVY7D3l2zxxSR0CxDGxrbo1nr79rmmpUTmEz0Cw80O84ZC1Ub2kA0WQ+LNhsvfubHg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794047687; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=IDmoBRN6QdTK+Ad0grSjoWU9YexwwymUIGmR3Z66XFA=; b=T+zbDrtq/32pzbNODI1RKZCAmCViO0Fbt3LtW19/jUvmvSBLIr3sqB9lJKk20X3dk7tw Ixie3PZkCa9XxhMSCzgI6mOYrY2YxQt+aZUSviBR/Hna2w51iMnCrtxWZXEfbnDrOowfi wrbTduqkLDACEvt1Fk6Pri9HQuHRaCryEPfONc44tcRwiYpqkeHW3tgriQhZ8rNPEos1I 1Grqz9oa5WzDmcS3WDBD/MXia/c3SUueMpbnwsN1D2MA0vdoJLpDbaDWWLFJ+6GRGgHKv X0SbtnnoVl6H6ROaZMgpUDN34K9inJoJqUXZPv4/ylzDE6m7cCiRFvKYJ/t5f5tejoA== 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=YnrblVHs; 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 BC211606A32D for ; Sat, 7 Nov 2026 10:34:46 +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=YnrblVHs Received: by smtp.kernel.org (Postfix) with ESMTPSA id 39FD81F0089F; Sat, 7 Nov 2026 10:34:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794047686; bh=IDmoBRN6QdTK+Ad0grSjoWU9YexwwymUIGmR3Z66XFA=; h=From:To:Cc:Subject:Date; b=YnrblVHszKV6GTYMWuC7g1GA/DfZalHSNi+7sN2C+eR3gnj5O+JaqFx5ADMl84ptW PHpRDe0OjtVwuBwagKrR+V1Mq52oz4k0u5QnKP5i7K9270VgdFUU/UrtIfPmNLJ7iH 9tVEuDRGn3rlgMr5Z0IYCVt9MoIQc8Igi0gkI/85ZAjgcukBu7dvRlOfC5CtZ4y3hL XB0rHuxciRNRXOwp5fAMN40whgOF/iguMZfQ81UXLhvhHPWatllM1NGt58W/1FSp5k xAvMexm6X9I42t3RhBTCq35+LhLyq9ywcxwvy50Uvb6FgcmHPhGZd1O4SVV633eF70 QN9MUCquzcy+g== From: Sasha Levin To: chao@kernel.org, jaegeuk@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] f2fs: fix to invalidate curseg if change_curseg() fails" failed to apply to 6.6-stable tree Date: Sat, 7 Nov 2026 05:34:45 -0500 Message-ID: <20261107053445-failed-6.6-e74476ad8162@kernel.org> X-Mailer: git-send-email 2.53.0 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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x e74476ad8162c1facc74b74ce2d1372492df872e # git commit -s git send-email --to '' --in-reply-to '20261107053445-failed-6.6-e74476ad8162@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From e74476ad8162c1facc74b74ce2d1372492df872e Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Tue, 13 Oct 2026 10:55:38 +0000 Subject: [PATCH] f2fs: fix to invalidate curseg if change_curseg() fails 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 --- fs/f2fs/segment.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index dab66ab3311d5..453f9284ec863 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -3243,6 +3243,7 @@ static int change_curseg(struct f2fs_sb_info *sbi, int type) if (IS_ERR(entry)) { /* GC won't be able to use stale summary blocks by cp_error */ memset(curseg->sum_blk, 0, sbi->sum_entry_size); + reset_curseg_fields(curseg); return PTR_ERR(entry); } sum_node = SUM_BLK_ENTRY_ADDR(sbi, entry, new_segno); -- 2.53.0