[Bug 204371] BUG kmalloc-4k (Tainted: G W ): Object padding overwritten

[Michael Ellerman]

bugzilla-daemon at bugzilla.kernel.org writes:
> https://bugzilla.kernel.org/show_bug.cgi?id=204371
>
> --- Comment #10 from David Sterba (dsterba at suse.com) ---
> In my case it happened on 5.3-rc3, with a strestest. The same machine has been
> running fstests periodically, with slab debug on, but there are no slab reports
> like that.
>
> [ 8516.870046] BUG kmalloc-4k (Not tainted): Poison overwritten                 
> [ 8516.875873]
> -----------------------------------------------------------------------------   
>
> [ 8516.885864] Disabling lock debugging due to kernel taint                     
> [ 8516.891312] INFO: 0x000000001c70c8c9-0x000000003cd1e164. First byte 0x16
> instead of 0x6b                                                                 
> [ 8516.899717] INFO: Allocated in btrfs_read_tree_root+0x46/0x120 [btrfs]
> age=1769 cpu=7 pid=8717                                                         
> [ 8516.908544]  __slab_alloc.isra.53+0x3e/0x70                                  
> [ 8516.912861]  kmem_cache_alloc_trace+0x1b0/0x330                              
> [ 8516.917581]  btrfs_read_tree_root+0x46/0x120 [btrfs]                         
> [ 8516.922737]  btrfs_read_fs_root+0xe/0x40 [btrfs]                             
> [ 8516.927552]  create_reloc_root+0x17f/0x2a0 [btrfs]                           
> [ 8516.932536]  btrfs_init_reloc_root+0x72/0xe0 [btrfs]                         
> [ 8516.937686]  record_root_in_trans+0xbb/0xf0 [btrfs]                          
> [ 8516.942750]  btrfs_record_root_in_trans+0x50/0x70 [btrfs]                    
> [ 8516.948340]  start_transaction+0xa1/0x550 [btrfs]                            
> [ 8516.953237]  __btrfs_prealloc_file_range+0xca/0x490 [btrfs]                  
> [ 8516.959003]  btrfs_prealloc_file_range+0x10/0x20 [btrfs]                     
> [ 8516.964509]  prealloc_file_extent_cluster+0x13e/0x2b0 [btrfs]                
> [ 8516.970447]  relocate_file_extent_cluster+0x8d/0x530 [btrfs]                 
> [ 8516.976305]  relocate_data_extent+0x80/0x110 [btrfs]                         
> [ 8516.981469]  relocate_block_group+0x473/0x720 [btrfs]                        
> [ 8516.986711]  btrfs_relocate_block_group+0x15f/0x2c0 [btrfs]                  

So this is looking more like it could be a btrfs bug, given you've both
hit it using btrfs but on different platforms.

cheers