Re: slab-out-of-bounds in rpc/nfs

From: Dmitry Vyukov
Date: Tue Mar 08 2016 - 05:38:07 EST


On Tue, Mar 8, 2016 at 11:27 AM, Benjamin Coddington
<bcodding@xxxxxxxxxx> wrote:
> Adding linux-nfs@xxxxxxxxxxxxxxx ..
>
> On Mon, 7 Mar 2016, Alexei Starovoitov wrote:
>
>> seeing on ton of these errors on net-next with kasan on.
>> Likely old bug though.
>>
>> [ 373.705691] BUG: KASAN: slab-out-of-bounds in memcpy+0x28/0x40 at
>> addr ffff8811ada62cb0
>> [ 373.707137] Write of size 28 by task bash/7059
>> [ 373.708177] =============================================================================
>> [ 373.709711] BUG kmalloc-4096 (Tainted: G W ): kasan:
>> bad access detected
>> [ 373.711185] -----------------------------------------------------------------------------
>> [ 373.711185]
>> [ 373.721461] INFO: Allocated in rpc_malloc+0x58/0xd0 age=21 cpu=5 pid=7059
>> [ 373.727158] ___slab_alloc+0x4e2/0x500
>> [ 373.728469] __slab_alloc+0x43/0x70
>> [ 373.729222] __kmalloc+0x286/0x350
>> [ 373.729978] rpc_malloc+0x58/0xd0
>> [ 373.730590] call_allocate+0x333/0x690
>> [ 373.731428] __rpc_execute+0x187/0xad0
>> [ 373.734395] rpc_execute+0xe1/0x2c0
>> [ 373.735020] rpc_run_task+0x1ce/0x250
>> [ 373.735706] rpc_call_sync+0x93/0x150
>> [ 373.736387] nfs3_rpc_wrapper.constprop.12+0x9b/0x240
>> [ 373.742818] nfs3_proc_readdir+0x230/0x390
>> [ 373.750157] nfs_readdir_xdr_to_array+0x501/0x9b0
>> [ 373.753520] nfs_readdir_filler+0x68/0x160
>> [ 373.758455] do_read_cache_page+0x8c/0x3c0
>> [ 373.761745] read_cache_page+0x46/0x70
>> [ 373.763269] nfs_readdir+0x420/0x1380
>> [ 373.764078] INFO: Freed in rpc_free+0x41/0x70 age=64 cpu=5 pid=7059
>> [ 373.765335] __slab_free+0x175/0x280
>> [ 373.766106] kfree+0x25c/0x2a0
>> [ 373.766809] rpc_free+0x41/0x70
>> [ 373.767629] xprt_release+0x2c5/0x8f0
>> [ 373.768430] rpc_release_resources_task+0x14/0x80
>> [ 373.769403] __rpc_execute+0x547/0xad0
>> [ 373.770249] rpc_execute+0xe1/0x2c0
>> [ 373.770995] rpc_run_task+0x1ce/0x250
>> [ 373.771786] rpc_call_sync+0x93/0x150
>> [ 373.772672] nfs3_rpc_wrapper.constprop.12+0x9b/0x240
>> [ 373.773704] nfs3_proc_access+0x1f1/0x330
>> [ 373.774544] nfs_do_access+0x94f/0x12d0
>> [ 373.775572] nfs_permission+0x469/0x580
>> [ 373.776465] __inode_permission+0x151/0x230
>> [ 373.780764] inode_permission+0x21/0xf0
>> [ 373.791392] may_open+0x14b/0x260
>>

The report misses the most interesting part -- the out-of-bounds
access stack. It should be at the bottom of the report. If you still
have the full report, please post it.