The patch below does not apply to the 4.4-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 stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b2ca374f33bd33fd822eb871876e4888cf79dc97 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim jaegeuk@kernel.org Date: Tue, 24 Apr 2018 15:44:16 -0600 Subject: [PATCH] f2fs: sanity check on sit entry
syzbot hit the following crash on upstream commit 87ef12027b9b1dd0e0b12cf311fbcb19f9d92539 (Wed Apr 18 19:48:17 2018 +0000) Merge tag 'ceph-for-4.17-rc2' of git://github.com/ceph/ceph-client syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=83699adeb2d13579c31e
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5805208181407744 syzkaller reproducer: https://syzkaller.appspot.com/x/repro.syz?id=6005073343676416 Raw console output: https://syzkaller.appspot.com/x/log.txt?id=6555047731134464 Kernel config: https://syzkaller.appspot.com/x/.config?id=1808800213120130118 compiler: gcc (GCC) 8.0.1 20180413 (experimental)
IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+83699adeb2d13579c31e@syzkaller.appspotmail.com It will help syzbot understand when the bug is fixed. See footer for details. If you forward the report, please keep this part and the footer.
F2FS-fs (loop0): Magic Mismatch, valid(0xf2f52010) - read(0x0) F2FS-fs (loop0): Can't find valid F2FS filesystem in 1th superblock F2FS-fs (loop0): invalid crc value BUG: unable to handle kernel paging request at ffffed006b2a50c0 PGD 21ffee067 P4D 21ffee067 PUD 21fbeb067 PMD 0 Oops: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 4514 Comm: syzkaller989480 Not tainted 4.17.0-rc1+ #8 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:build_sit_entries fs/f2fs/segment.c:3653 [inline] RIP: 0010:build_segment_manager+0x7ef7/0xbf70 fs/f2fs/segment.c:3852 RSP: 0018:ffff8801b102e5b0 EFLAGS: 00010a06 RAX: 1ffff1006b2a50c0 RBX: 0000000000000004 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8801ac74243e RBP: ffff8801b102f410 R08: ffff8801acbd46c0 R09: fffffbfff14d9af8 R10: fffffbfff14d9af8 R11: ffff8801acbd46c0 R12: ffff8801ac742a80 R13: ffff8801d9519100 R14: dffffc0000000000 R15: ffff880359528600 FS: 0000000001e04880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffed006b2a50c0 CR3: 00000001ac6ac000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: f2fs_fill_super+0x4095/0x7bf0 fs/f2fs/super.c:2803 mount_bdev+0x30c/0x3e0 fs/super.c:1165 f2fs_mount+0x34/0x40 fs/f2fs/super.c:3020 mount_fs+0xae/0x328 fs/super.c:1268 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2517 [inline] do_mount+0x564/0x3070 fs/namespace.c:2847 ksys_mount+0x12d/0x140 fs/namespace.c:3063 __do_sys_mount fs/namespace.c:3077 [inline] __se_sys_mount fs/namespace.c:3074 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3074 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x443d6a RSP: 002b:00007ffd312813c8 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000c00 RCX: 0000000000443d6a RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffd312813d0 RBP: 0000000000000003 R08: 0000000020016a00 R09: 000000000000000a R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000004 R13: 0000000000402c60 R14: 0000000000000000 R15: 0000000000000000 RIP: build_sit_entries fs/f2fs/segment.c:3653 [inline] RSP: ffff8801b102e5b0 RIP: build_segment_manager+0x7ef7/0xbf70 fs/f2fs/segment.c:3852 RSP: ffff8801b102e5b0 CR2: ffffed006b2a50c0 ---[ end trace a2034989e196ff17 ]---
Reported-and-tested-by: syzbot+83699adeb2d13579c31e@syzkaller.appspotmail.com Reviewed-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 1dc7a3d20786..3ba8a4a768c9 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -3681,6 +3681,15 @@ static int build_sit_entries(struct f2fs_sb_info *sbi) unsigned int old_valid_blocks;
start = le32_to_cpu(segno_in_journal(journal, i)); + if (start >= MAIN_SEGS(sbi)) { + f2fs_msg(sbi->sb, KERN_ERR, + "Wrong journal entry on segno %u", + start); + set_sbi_flag(sbi, SBI_NEED_FSCK); + err = -EINVAL; + break; + } + se = &sit_i->sentries[start]; sit = sit_in_journal(journal, i);