• Edward Adam Davis's avatar
    gfs2: fix kernel BUG in gfs2_quota_cleanup · 71733b49
    Edward Adam Davis authored
    [Syz report]
    kernel BUG at fs/gfs2/quota.c:1508!
    invalid opcode: 0000 [#1] PREEMPT SMP KASAN
    CPU: 0 PID: 5060 Comm: syz-executor505 Not tainted 6.7.0-rc3-syzkaller-00134-g994d5c58 #0
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
    RIP: 0010:gfs2_quota_cleanup+0x6b5/0x6c0 fs/gfs2/quota.c:1508
    Code: fe e9 cf fd ff ff 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c 2d fe ff ff 4c 89 ef e8 b6 19 23 fe e9 20 fe ff ff e8 ec 11 c7 fd 90 <0f> 0b e8 84 9c 4f 07 0f 1f 40 00 66 0f 1f 00 55 41 57 41 56 41 54
    RSP: 0018:ffffc9000409f9e0 EFLAGS: 00010293
    RAX: ffffffff83c76854 RBX: 0000000000000002 RCX: ffff888026001dc0
    RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
    RBP: ffffc9000409fb00 R08: ffffffff83c762b0 R09: 1ffff1100fd38015
    R10: dffffc0000000000 R11: ffffed100fd38016 R12: dffffc0000000000
    R13: ffff88807e9c0828 R14: ffff888014693580 R15: ffff88807e9c0000
    FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007f16d1bd70f8 CR3: 0000000027199000 CR4: 00000000003506f0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    Call Trace:
     <TASK>
     gfs2_put_super+0x2e1/0x940 fs/gfs2/super.c:611
     generic_shutdown_super+0x13a/0x2c0 fs/super.c:696
     kill_block_super+0x44/0x90 fs/super.c:1667
     deactivate_locked_super+0xc1/0x130 fs/super.c:484
     cleanup_mnt+0x426/0x4c0 fs/namespace.c:1256
     task_work_run+0x24a/0x300 kernel/task_work.c:180
     exit_task_work include/linux/task_work.h:38 [inline]
     do_exit+0xa34/0x2750 kernel/exit.c:871
     do_group_exit+0x206/0x2c0 kernel/exit.c:1021
     __do_sys_exit_group kernel/exit.c:1032 [inline]
     __se_sys_exit_group kernel/exit.c:1030 [inline]
     __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1030
     do_syscall_x64 arch/x86/entry/common.c:51 [inline]
     do_syscall_64+0x45/0x110 arch/x86/entry/common.c:82
     entry_SYSCALL_64_after_hwframe+0x63/0x6b
    ...
    
    [pid  5060] fsconfig(4, FSCONFIG_CMD_RECONFIGURE, NULL, NULL, 0) = 0
    [pid  5060] exit_group(1)               = ?
    ...
    
    [Analysis]
    When the task exits, it will execute cleanup_mnt() to recycle the mounted gfs2
    file system, but it performs a system call fsconfig(4, FSCONFIG_CMD_RECONFIGURE,
    NULL, NULL, 0) before executing the task exit operation.
    
    This will execute the following kernel path to complete the setting of
    SDF_JOURNAL_LIVE for sd_flags:
    
    SYSCALL_DEFINE5(fsconfig, ..)->
    	vfs_fsconfig_locked()->
    		vfs_cmd_reconfigure()->
    			gfs2_reconfigure()->
    				gfs2_make_fs_rw()->
    					set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
    
    [Fix]
    Add SDF_NORECOVERY check in gfs2_quota_cleanup() to avoid checking
    SDF_JOURNAL_LIVE on the path where gfs2 is being unmounted.
    
    Reported-and-tested-by: syzbot+3b6e67ac2b646da57862@syzkaller.appspotmail.com
    Fixes: f66af88e ("gfs2: Stop using gfs2_make_fs_ro for withdraw")
    Signed-off-by: default avatarEdward Adam Davis <eadavis@qq.com>
    Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
    71733b49
quota.c 43.1 KB