On Wed, Feb 05, 2020 at 12:02:11PM +0800, Zorro Lang wrote:
> On Tue, Feb 04, 2020 at 04:09:10PM -0800, Darrick J. Wong wrote:
> > On Wed, Feb 05, 2020 at 08:39:32AM +1100, Dave Chinner wrote:
> > > On Tue, Feb 04, 2020 at 03:06:36PM +0800, Zorro Lang wrote:
> > > > This patch fixes below KASAN report. The xfs_attr3_node_inactive()
> > > > gets 'child_bp' at there:
> > > > error = xfs_trans_get_buf(*trans, mp->m_ddev_targp,
> > > > child_blkno,
> > > > XFS_FSB_TO_BB(mp, mp->m_attr_geo->fsbcount), 0,
> > > > &child_bp);
> > > > if (error)
> > > > return error;
> > > > error = bp->b_error;
> > > >
> > > > But it turns to use 'bp', not 'child_bp'. And the 'bp' has been freed by:
> > > > xfs_trans_brelse(*trans, bp);
> > >
> > > ....
> > > > ---
> > > > fs/xfs/xfs_attr_inactive.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c
> > > > index bbfa6ba84dcd..26230d150bf2 100644
> > > > --- a/fs/xfs/xfs_attr_inactive.c
> > > > +++ b/fs/xfs/xfs_attr_inactive.c
> > > > @@ -211,7 +211,7 @@ xfs_attr3_node_inactive(
> > > > &child_bp);
> > > > if (error)
> > > > return error;
> > > > - error = bp->b_error;
> > > > + error = child_bp->b_error;
> > > > if (error) {
> > > > xfs_trans_brelse(*trans, child_bp);
> > > > return error;
> > >
> > > Isn't this dead code now? i.e. any error that occurs on the buffer
> > > during a xfs_trans_get_buf() call is returned directly and so it's
> > > caught by the "if (error)" check. Hence this whole child_bp->b_error
> > > check can be removed, right?
> >
> > It will be after I send in the second half of the 5.6 merge window. I
> > decided to hang onto the buffer error code rework until all of the
> > kernel fuzz tests finished running and I was satisfied with my own
> > userspace port of the same series.
> >
> > (All that is now done, so I'll send that to linus tomorrow.)
Hi,
Has this issue been fixed? Due to I still hit xfs/433 fail on latest xfs-linux:
[53972.827180] run fstests xfs/433 at 2020-10-24 23:11:10
[53975.984049] XFS (vda3): Mounting V5 Filesystem
[53976.134116] XFS (vda3): Ending clean mount
[53976.210045] xfs filesystem being mounted at /mnt/xfstests/scratch supports timestamps until 2038 (0x7fffffff)
[53982.471101] XFS (vda3): Unmounting Filesystem
[53982.823725] XFS (vda3): Mounting V5 Filesystem
[53982.876916] XFS (vda3): Ending clean mount
[53982.898987] xfs filesystem being mounted at /mnt/xfstests/scratch supports timestamps until 2038 (0x7fffffff)
[53982.949671] XFS (vda3): Injecting error (false) at file fs/xfs/xfs_buf.c, line 2345, on filesystem "vda3"
[53982.952998] XFS (vda3): Injecting error (false) at file fs/xfs/xfs_buf.c, line 2345, on filesystem "vda3"
[53982.957436] XFS (vda3): Injecting error (false) at file fs/xfs/xfs_buf.c, line 2345, on filesystem "vda3"
[53982.960791] XFS (vda3): Injecting error (false) at file fs/xfs/xfs_buf.c, line 2345, on filesystem "vda3"
[53982.963502] ==================================================================
[53982.966070] BUG: KASAN: use-after-free in xfs_attr3_node_inactive+0x684/0x7c0 [xfs]
[53982.968000] Read of size 4 at addr fffffc0106509854 by task rm/2847654
[53982.970018] CPU: 0 PID: 2847654 Comm: rm Tainted: G W 5.9.0-rc4 #1
[53982.971872] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
[53982.973583] Call trace:
[53982.974323] dump_backtrace+0x0/0x3d0
[53982.975267] show_stack+0x1c/0x28
[53982.976159] dump_stack+0x13c/0x1b8
[53982.977092] print_address_description.constprop.12+0x68/0x4e0
[53982.978575] kasan_report+0x134/0x1b8
[53982.979521] __asan_report_load4_noabort+0x2c/0x50
[53982.980876] xfs_attr3_node_inactive+0x684/0x7c0 [xfs]
[53982.982320] xfs_attr_inactive+0x414/0x7e8 [xfs]
[53982.983633] xfs_inactive+0x398/0x4e8 [xfs]
[53982.984835] xfs_fs_destroy_inode+0x440/0xf48 [xfs]
[53982.986080] destroy_inode+0xa8/0x178
[53982.987024] evict+0x2bc/0x4a8
[53982.987804] iput+0x504/0x8f8
[53982.988561] do_unlinkat+0x36c/0x480
[53982.989482] __arm64_sys_unlinkat+0x94/0xf0
[53982.990558] do_el0_svc+0x1c4/0x3c0
[53982.991442] el0_sync_handler+0xf8/0x124
[53982.992437] el0_sync+0x140/0x180
[53982.993669] Allocated by task 2847654:
[53982.994663] kasan_save_stack+0x24/0x50
[53982.995682] __kasan_kmalloc.isra.6+0xc4/0xe0
[53982.996798] kasan_slab_alloc+0x14/0x20
[53982.997768] slab_post_alloc_hook+0x5c/0x548
[53982.998846] kmem_cache_alloc+0x170/0x400
[53983.000016] _xfs_buf_alloc+0x68/0x1318 [xfs]
[53983.001249] xfs_buf_get_map+0x13c/0xcb8 [xfs]
[53983.002504] xfs_buf_read_map+0xbc/0xdc0 [xfs]
[53983.003765] xfs_trans_read_buf_map+0x534/0x1ff0 [xfs]
[53983.005209] xfs_da_read_buf+0x1ac/0x258 [xfs]
[53983.006487] xfs_da3_node_read+0x3c/0x98 [xfs]
[53983.007735] xfs_attr_inactive+0x5b8/0x7e8 [xfs]
[53983.009034] xfs_inactive+0x398/0x4e8 [xfs]
[53983.010240] xfs_fs_destroy_inode+0x440/0xf48 [xfs]
[53983.011507] destroy_inode+0xa8/0x178
[53983.012442] evict+0x2bc/0x4a8
[53983.013228] iput+0x504/0x8f8
[53983.013972] do_unlinkat+0x36c/0x480
[53983.014884] __arm64_sys_unlinkat+0x94/0xf0
[53983.015964] do_el0_svc+0x1c4/0x3c0
[53983.016864] el0_sync_handler+0xf8/0x124
[53983.017858] el0_sync+0x140/0x180
[53983.019086] Freed by task 2847654:
[53983.019946] kasan_save_stack+0x24/0x50
[53983.020953] kasan_set_track+0x24/0x38
[53983.021908] kasan_set_free_info+0x20/0x40
[53983.022940] __kasan_slab_free+0x100/0x170
[53983.023973] kasan_slab_free+0x10/0x18
[53983.024924] slab_free_freelist_hook+0xf8/0x260
[53983.026093] kmem_cache_free+0xd0/0x4b0
[53983.027205] xfs_buf_free+0x354/0x958 [xfs]
[53983.028399] xfs_buf_rele+0x1040/0x1a90 [xfs]
[53983.029643] xfs_trans_brelse+0x294/0x858 [xfs]
[53983.030941] xfs_attr3_node_inactive+0x1a4/0x7c0 [xfs]
[53983.032396] xfs_attr_inactive+0x414/0x7e8 [xfs]
[53983.033693] xfs_inactive+0x398/0x4e8 [xfs]
[53983.034889] xfs_fs_destroy_inode+0x440/0xf48 [xfs]
[53983.036143] destroy_inode+0xa8/0x178
[53983.037083] evict+0x2bc/0x4a8
[53983.037868] iput+0x504/0x8f8
[53983.038636] do_unlinkat+0x36c/0x480
[53983.039553] __arm64_sys_unlinkat+0x94/0xf0
[53983.040622] do_el0_svc+0x1c4/0x3c0
[53983.041515] el0_sync_handler+0xf8/0x124
[53983.042523] el0_sync+0x140/0x180
[53983.043750] The buggy address belongs to the object at fffffc0106509600
which belongs to the cache xfs_buf of size 632
[53983.046824] The buggy address is located 596 bytes inside of
632-byte region [fffffc0106509600, fffffc0106509878)
[53983.049772] The buggy address belongs to the page:
[53983.050993] page:00000000e91654da refcount:1 mapcount:0 mapping:0000000000000000 index:0xfffffc0106500000 pfn:0x14650
[53983.053681] flags: 0x17ffff8000000200(slab)
[53983.054748] raw: 17ffff8000000200 ffffffff7ffaaa80 0000000600000006 fffffc012154a380
[53983.056713] raw: fffffc0106500000 000000008055004a 00000001ffffffff 0000000000000000
[53983.058688] page dumped because: kasan: bad access detected
[53983.060494] Memory state around the buggy address:
[53983.061719] fffffc0106509700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[53983.063569] fffffc0106509780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[53983.065350] >fffffc0106509800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
[53983.067180] ^
[53983.068670] fffffc0106509880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[53983.070474] fffffc0106509900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[53983.072340] ==================================================================
>
> Oh, that's great! Please ignore this noise(/patch) :)
>
> Thanks,
> Zorro
>
> >
> > --D
> >
> > > Cheers,
> > >
> > > Dave.
> > > --
> > > Dave Chinner
> > > david@xxxxxxxxxxxxx
> >
>
