From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74D0B42B33F for ; Thu, 2 Jul 2026 13:11:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782997908; cv=none; b=JOucRbMHDusxGYtCc9DaARYdEB32cL2XS/2jYJj2KpC0ZxZ6mkOj7WipfkKy0Sf+zMAe0tMUtHAJPxpscDTZCBIweifjW1/RkEAWIMqCUzd1dV7UY0OJ9JXCUkAbZy7SpaW/eIGn9lYEDxDz3Q6bNjh28INIw5rApcR9NVxASQM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782997908; c=relaxed/simple; bh=+/q3vwrNhf1+nTySBdjpkrjzG76zrsxO/K8xsi7vBaY=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=cuMbgNxxn8tMUaj/FEYQXG2/sQWqj02EgVPmd/0Nbdd6ueDnvXKmvtGS/hkmv1iyTLRraBvflEBY3lUFU7VIcj3k8fegqc1lIBbS9ethYEzvOQasVxfjSPVgeETkOmE4MVUq+hYKEYEzMIvq0p+wJMZxWU0vP0T07WoUgHTZOwY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cZdqzjX1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="cZdqzjX1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8ACAB1F00A3A; Thu, 2 Jul 2026 13:11:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782997906; bh=X6UEhXowshm/AiKMwK1acceR/JrfYBumJpVmptF869I=; h=Subject:To:Cc:From:Date; b=cZdqzjX1fB6xHdxMp6fZpvULTdiyfGoRgZ2JrThboXmjtAZMN49n/CTQp2VSOj5+B apjeLa1AVt4maR46zahMDVSOHNRP7wAP7sgNxHLTFImenSb0fRNf0W712au95bUDp6 SZr/B8DVSPnn6Dc8g63zxI35v5MW8KL2jazTY1z4= Subject: FAILED: patch "[PATCH] f2fs: fix potential deadlock in gc_merge path of" failed to apply to 5.15-stable tree To: chao@kernel.org,chaseyu@google.com,dhavale@google.com,jaegeuk@kernel.org,ruipengqi3@gmail.com Cc: From: Date: Thu, 02 Jul 2026 15:11:42 +0200 Message-ID: <2026070242-embassy-abdominal-7557@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x 8b4468ec023d0d1b4669dfb867588997cc03a06b # git commit -s git send-email --to '' --in-reply-to '2026070242-embassy-abdominal-7557@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 8b4468ec023d0d1b4669dfb867588997cc03a06b Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Tue, 19 May 2026 01:14:38 +0000 Subject: [PATCH] f2fs: fix potential deadlock in gc_merge path of f2fs_balance_fs() When we mount device w/ gc_merge mount option, we may suffer below potential deadlock: Kworker GC trehad Truncator - f2fs_write_cache_pages - f2fs_write_single_data_page - f2fs_do_write_data_page - folio_start_writeback --- set writeback flag on folio - f2fs_outplace_write_data : cached folio in internal bio cache - f2fs_balance_fs - wake_up(gc_thread) : wake up gc thread to run foreground GC - finish_wait(fggc_wq) : wait on the waitqueue --- wait on GC thread to finish the work - truncate_inode_pages_range - __filemap_get_folio(, FGP_LOCK) --- lock folio - truncate_inode_partial_folio - folio_wait_writeback --- wait on writeback being cleared - do_garbage_collect - move_data_page - f2fs_get_lock_data_folio - lock on folio --- blocked on folio's lock In order to avoid such deadlock, let's call below functions to commit cached bios in GC_MERGE path of f2fs_balance_fs() as the same as we did in NOGC_MERGE path. - f2fs_submit_merged_write(sbi, DATA); - f2fs_submit_all_merged_ipu_writes(sbi); Cc: stable@kernel.org Fixes: 351df4b20115 ("f2fs: add segment operations") Cc: Ruipeng Qi Reported: Sandeep Dhavale Signed-off-by: Chao Yu Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 7c8ac62b1b0d..1ef4edb77078 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -445,6 +445,13 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) if (has_enough_free_secs(sbi, 0, 0)) return; + /* + * Submit all cached OPU/IPU DATA bios before triggering + * foreground GC to avoid potential deadlocks. + */ + f2fs_submit_merged_write(sbi, DATA); + f2fs_submit_all_merged_ipu_writes(sbi); + if (test_opt(sbi, GC_MERGE) && sbi->gc_thread && sbi->gc_thread->f2fs_gc_task) { DEFINE_WAIT(wait); @@ -464,13 +471,6 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) .err_gc_skipped = false, .nr_free_secs = 1 }; - /* - * Submit all cached OPU/IPU DATA bios before triggering - * foreground GC to avoid potential deadlocks. - */ - f2fs_submit_merged_write(sbi, DATA); - f2fs_submit_all_merged_ipu_writes(sbi); - f2fs_down_write_trace(&sbi->gc_lock, &gc_control.lc); stat_inc_gc_call_count(sbi, FOREGROUND); f2fs_gc(sbi, &gc_control);