On Thu, Nov 19, 2020 at 9:37 AM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: > > Hi Olga- > > > On Nov 18, 2020, at 4:44 PM, Olga Kornievskaia <olga.kornievskaia@xxxxxxxxx> wrote: > > > > Hi Chuck, > > > > The first problem I found was from 5.10-rc3 testing was from the fact > > that tail's iov_len was set to -4 and reply_chunk was trying to call > > rpcrdma_convert_kvec() for a tail that didn't exist. > > > > Do you see issues with this fix? > > > > diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c > > index 71e03b930b70..2e6a228abb95 100644 > > --- a/net/sunrpc/xdr.c > > +++ b/net/sunrpc/xdr.c > > @@ -193,7 +193,7 @@ xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset, > > > > tail->iov_base = buf + offset; > > tail->iov_len = buflen - offset; > > - if ((xdr->page_len & 3) == 0) > > + if ((xdr->page_len & 3) == 0 && tail->iov_len) > > tail->iov_len -= sizeof(__be32); > > > > xdr->buflen += len; > > It's not clear to me whether only the listxattrs encoder is > not providing a receive tail kvec, or whether all the encoders > fail to provide a tail in this case. There is nothing specific that listxattr does, it just calls rpc_prepare_pages(). Isn't tail[0] always there (xdr_buf structure has tail[1] defined)? But not all requests have data in the page. So as far as I understand, tail->iov_len can be 0 so not checking for it is wrong. > > This one fixes KASAN's reported problem of added at the end of this message. > > > > The next problem that I can't figure out yet is another KASAN's report > > during the completion of the request. > > > > [ 99.610666] BUG: KASAN: wild-memory-access in > > rpcrdma_complete_rqst+0x41b/0x680 [rpcrdma] > > [ 99.617947] Write of size 4 at addr 0005088000000000 by task kworker/1:1H/490 > > > > > > This is the KASAN for the negative tail problem: > > [ 665.767611] ================================================================== > > [ 665.772202] BUG: KASAN: slab-out-of-bounds in > > rpcrdma_convert_kvec.isra.29+0x4a/0xc4 [rpcrdma] > > [ 665.777860] Write of size 8 at addr ffff88803ded9b70 by task fsstress/3123 > > [ 665.783754] > > [ 665.784981] CPU: 0 PID: 3123 Comm: fsstress Not tainted 5.10.0-rc3+ #38 > > [ 665.790534] Hardware name: VMware, Inc. VMware Virtual > > Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020 > > [ 665.798538] Call Trace: > > [ 665.800398] dump_stack+0x7c/0xa2 > > [ 665.802647] ? rpcrdma_convert_kvec.isra.29+0x4a/0xc4 [rpcrdma] > > [ 665.808145] print_address_description.constprop.7+0x1e/0x230 > > [ 665.812543] ? record_print_text.cold.38+0x11/0x11 > > [ 665.816093] ? _raw_write_lock_irqsave+0xe0/0xe0 > > [ 665.819257] ? rpcrdma_convert_kvec.isra.29+0x4a/0xc4 [rpcrdma] > > [ 665.823368] ? rpcrdma_convert_kvec.isra.29+0x4a/0xc4 [rpcrdma] > > [ 665.827837] kasan_report.cold.9+0x37/0x7c > > [ 665.830076] ? rpcrdma_convert_kvec.isra.29+0x4a/0xc4 [rpcrdma] > > [ 665.834066] rpcrdma_convert_kvec.isra.29+0x4a/0xc4 [rpcrdma] > > [ 665.837342] rpcrdma_convert_iovs.isra.30.cold.41+0x9b/0xa0 [rpcrdma] > > [ 665.841766] ? decode_read_list+0x40/0x40 [rpcrdma] > > [ 665.845063] ? _raw_spin_lock_irqsave+0x80/0xe0 > > [ 665.848444] ? xdr_reserve_space+0x12e/0x360 [sunrpc] > > [ 665.852186] ? xdr_init_encode+0x104/0x130 [sunrpc] > > [ 665.855305] rpcrdma_marshal_req.cold.43+0x39/0x1fa [rpcrdma] > > [ 665.859771] ? _raw_spin_lock+0x7a/0xd0 > > [ 665.862516] ? rpcrdma_prepare_send_sges+0x7e0/0x7e0 [rpcrdma] > > [ 665.866533] ? call_bind+0x60/0xf0 [sunrpc] > > [ 665.869382] xprt_rdma_send_request+0x79/0x190 [rpcrdma] > > [ 665.872965] xprt_transmit+0x2ae/0x6c0 [sunrpc] > > [ 665.875955] ? call_bind+0xf0/0xf0 [sunrpc] > > [ 665.878372] call_transmit+0xdd/0x110 [sunrpc] > > [ 665.881539] ? call_bind+0xf0/0xf0 [sunrpc] > > [ 665.884629] __rpc_execute+0x11c/0x6e0 [sunrpc] > > [ 665.888300] ? trace_event_raw_event_xprt_cong_event+0x270/0x270 [sunrpc] > > [ 665.893935] ? rpc_make_runnable+0x54/0xe0 [sunrpc] > > [ 665.898021] rpc_run_task+0x29c/0x2c0 [sunrpc] > > [ 665.901142] nfs4_call_sync_custom+0xc/0x40 [nfsv4] > > [ 665.904903] nfs4_do_call_sync+0x114/0x160 [nfsv4] > > [ 665.908633] ? nfs4_call_sync_custom+0x40/0x40 [nfsv4] > > [ 665.913094] ? __alloc_pages_nodemask+0x200/0x410 > > [ 665.916831] ? kasan_unpoison_shadow+0x30/0x40 > > [ 665.920393] ? __kasan_kmalloc.constprop.8+0xc1/0xd0 > > [ 665.924403] _nfs42_proc_listxattrs+0x1f6/0x2f0 [nfsv4] > > [ 665.928552] ? kasan_set_free_info+0x1b/0x30 > > [ 665.932283] ? nfs42_offload_cancel_done+0x50/0x50 [nfsv4] > > [ 665.936240] ? _raw_spin_lock+0x7a/0xd0 > > [ 665.938677] nfs42_proc_listxattrs+0xf4/0x150 [nfsv4] > > [ 665.942532] ? nfs42_proc_setxattr+0x150/0x150 [nfsv4] > > [ 665.946410] ? nfs4_xattr_cache_list+0x21/0x120 [nfsv4] > > [ 665.950095] nfs4_listxattr+0x34d/0x3d0 [nfsv4] > > [ 665.952951] ? _nfs4_proc_access+0x260/0x260 [nfsv4] > > [ 665.956383] ? __ia32_sys_rename+0x40/0x40 > > [ 665.959559] ? __ia32_sys_lstat+0x30/0x30 > > [ 665.962519] ? __check_object_size+0x178/0x220 > > [ 665.965830] ? strncpy_from_user+0xe9/0x230 > > [ 665.968401] ? security_inode_listxattr+0x20/0x60 > > [ 665.971653] listxattr+0xd1/0xf0 > > [ 665.974065] path_listxattr+0xa1/0x100 > > [ 665.977023] ? listxattr+0xf0/0xf0 > > [ 665.979305] do_syscall_64+0x33/0x40 > > [ 665.981561] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > [ 665.985559] RIP: 0033:0x7fe3f5a1fc8b > > [ 665.988136] Code: f0 ff ff 73 01 c3 48 8b 0d fa 21 2c 00 f7 d8 64 > > 89 01 48 83 c8 ff c3 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 c2 00 00 > > 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d cd 21 2c 00 f7 d8 64 89 > > 01 48 > > [ 666.002248] RSP: 002b:00007ffc826128e8 EFLAGS: 00000206 ORIG_RAX: > > 00000000000000c2 > > [ 666.007760] RAX: ffffffffffffffda RBX: 0000000000000021 RCX: 00007fe3f5a1fc8b > > [ 666.012999] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000016eaf70 > > [ 666.018963] RBP: 00000000000001f4 R08: 0000000000000000 R09: 00007ffc82612537 > > [ 666.025553] R10: 0000000000000004 R11: 0000000000000206 R12: 0000000000000021 > > [ 666.030600] R13: 0000000000403e60 R14: 0000000000000000 R15: 0000000000000000 > > [ 666.035780] > > [ 666.036906] Allocated by task 2837: > > [ 666.039447] kasan_save_stack+0x19/0x40 > > [ 666.042815] __kasan_kmalloc.constprop.8+0xc1/0xd0 > > [ 666.046626] rpcrdma_req_create+0x58/0x1f0 [rpcrdma] > > [ 666.050283] rpcrdma_buffer_create+0x217/0x270 [rpcrdma] > > [ 666.053727] xprt_setup_rdma+0x1a3/0x2c0 [rpcrdma] > > [ 666.057287] xprt_create_transport+0xc7/0x300 [sunrpc] > > [ 666.061656] rpc_create+0x185/0x360 [sunrpc] > > [ 666.064803] nfs_create_rpc_client+0x2d9/0x350 [nfs] > > [ 666.068233] nfs4_init_client+0x111/0x3d0 [nfsv4] > > [ 666.071563] nfs4_set_client+0x18c/0x2b0 [nfsv4] > > [ 666.075287] nfs4_create_server+0x303/0x590 [nfsv4] > > [ 666.079563] nfs4_try_get_tree+0x60/0xe0 [nfsv4] > > [ 666.082835] vfs_get_tree+0x45/0x120 > > [ 666.085165] path_mount+0x8da/0xcc0 > > [ 666.087352] do_mount+0xcb/0xf0 > > [ 666.089377] __x64_sys_mount+0xf4/0x110 > > [ 666.091894] do_syscall_64+0x33/0x40 > > [ 666.094215] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > [ 666.097181] > > [ 666.098548] The buggy address belongs to the object at ffff88803ded8000 > > [ 666.098548] which belongs to the cache kmalloc-8k of size 8192 > > [ 666.108266] The buggy address is located 7024 bytes inside of > > [ 666.108266] 8192-byte region [ffff88803ded8000, ffff88803deda000) > > [ 666.115709] The buggy address belongs to the page: > > [ 666.118516] page:00000000e08a579f refcount:1 mapcount:0 > > mapping:0000000000000000 index:0x0 pfn:0x3ded8 > > [ 666.124078] head:00000000e08a579f order:3 compound_mapcount:0 > > compound_pincount:0 > > [ 666.130104] flags: 0xfffffc0010200(slab|head) > > [ 666.133692] raw: 000fffffc0010200 dead000000000100 dead000000000122 > > ffff88800104ee40 > > [ 666.139286] raw: 0000000000000000 0000000000020002 00000001ffffffff > > 0000000000000000 > > [ 666.145052] page dumped because: kasan: bad access detected > > [ 666.149341] > > [ 666.150408] Memory state around the buggy address: > > -- > Chuck Lever > > >
