While using wget to download a 100MB+ file onto a nfs share I got the following Oops: Apr 5 19:53:59 thoregon kernel: [ 1726.918412] BUG: unable to handle kernel NULL pointer dereference at 0000000000000048 Apr 5 19:53:59 thoregon kernel: [ 1726.918455] IP: [<ffffffff81151821>] nfs_clear_request_commit+0x11/0x90 Apr 5 19:53:59 thoregon kernel: [ 1726.918489] PGD 1e6300067 PUD 21175c067 PMD 0 Apr 5 19:53:59 thoregon kernel: [ 1726.918511] Oops: 0000 [#1] SMP Apr 5 19:53:59 thoregon kernel: [ 1726.918527] CPU 5 Apr 5 19:53:59 thoregon kernel: [ 1726.918536] Modules linked in: fuse Apr 5 19:53:59 thoregon kernel: [ 1726.918554] Apr 5 19:53:59 thoregon kernel: [ 1726.918562] Pid: 11486, comm: wget Not tainted 3.4.0-rc1 #1 MSI MS-7640/890FXA-GD70 (MS-7640) Apr 5 19:53:59 thoregon kernel: [ 1726.918600] RIP: 0010:[<ffffffff81151821>] [<ffffffff81151821>] nfs_clear_request_commit+0x11/0x90 Apr 5 19:53:59 thoregon kernel: [ 1726.918639] RSP: 0018:ffff8801e546fb08 EFLAGS: 00010292 Apr 5 19:53:59 thoregon kernel: [ 1726.918660] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000180200000 Apr 5 19:53:59 thoregon kernel: [ 1726.918689] RDX: 4000000000000029 RSI: 0000000000000001 RDI: 0000000000000000 Apr 5 19:53:59 thoregon kernel: [ 1726.918717] RBP: 000000000000078c R08: 0000000000000000 R09: ffffffff81152d68 Apr 5 19:53:59 thoregon kernel: [ 1726.918745] R10: ffffffff8114d54a R11: 0000000000000000 R12: ffff8802312c73a8 Apr 5 19:53:59 thoregon kernel: [ 1726.918774] R13: 0000000000000874 R14: ffff8803291a2580 R15: 0000000000000000 Apr 5 19:53:59 thoregon kernel: [ 1726.918803] FS: 00007f7b3a65d720(0000) GS:ffff880337d40000(0000) knlGS:0000000000000000 Apr 5 19:53:59 thoregon kernel: [ 1726.918835] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Apr 5 19:53:59 thoregon kernel: [ 1726.918858] CR2: 0000000000000048 CR3: 000000021e3c0000 CR4: 00000000000007e0 Apr 5 19:53:59 thoregon kernel: [ 1726.918887] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Apr 5 19:53:59 thoregon kernel: [ 1726.918915] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Apr 5 19:53:59 thoregon kernel: [ 1726.918944] Process wget (pid: 11486, threadinfo ffff8801e546e000, task ffff8801d2decac0) Apr 5 19:53:59 thoregon kernel: [ 1726.918976] Stack: Apr 5 19:53:59 thoregon kernel: [ 1726.918985] 000000000000078c ffffea0006d484c0 000000000000078c ffffffff81152d98 Apr 5 19:53:59 thoregon kernel: [ 1726.919020] ffff8802312c74e0 ffffffff00000000 ffff8802312c7420 0000100006d484c0 Apr 5 19:53:59 thoregon kernel: [ 1726.919053] ffff8803291a2580 ffff880235f43c00 0000000000000874 ffffea0006d484c0 Apr 5 19:53:59 thoregon kernel: [ 1726.919086] Call Trace: Apr 5 19:53:59 thoregon kernel: [ 1726.919099] [<ffffffff81152d98>] ? nfs_updatepage+0x1e8/0x3d0 Apr 5 19:53:59 thoregon kernel: [ 1726.919124] [<ffffffff811445c9>] ? nfs_write_end+0x129/0x250 Apr 5 19:53:59 thoregon kernel: [ 1726.919149] [<ffffffff8108e46b>] ? generic_file_buffered_write+0x19b/0x2c0 Apr 5 19:53:59 thoregon kernel: [ 1726.919179] [<ffffffff8108ffb1>] ? __generic_file_aio_write+0x211/0x410 Apr 5 19:53:59 thoregon kernel: [ 1726.919207] [<ffffffff81090226>] ? generic_file_aio_write+0x76/0xf0 Apr 5 19:53:59 thoregon kernel: [ 1726.919233] [<ffffffff8114439b>] ? nfs_file_write+0x7b/0x180 Apr 5 19:53:59 thoregon kernel: [ 1726.919258] [<ffffffff810cf4df>] ? do_sync_write+0xbf/0x100 Apr 5 19:53:59 thoregon kernel: [ 1726.919282] [<ffffffff810cfd16>] ? vfs_write+0xc6/0x170 Apr 5 19:53:59 thoregon kernel: [ 1726.919304] [<ffffffff810cfffe>] ? sys_write+0x4e/0x90 Apr 5 19:53:59 thoregon kernel: [ 1726.919328] [<ffffffff815f7822>] ? system_call_fastpath+0x16/0x1b Apr 5 19:53:59 thoregon kernel: [ 1726.919352] Code: 00 00 e8 f3 4d 11 00 53 9d 5b c3 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec 18 48 89 5c 24 08 48 89 6c 24 10 48 89 fb <48> 8b 47 48 a8 04 74 47 48 8b 47 18 48 8b 40 30 48 8b 68 30 48 Apr 5 19:53:59 thoregon kernel: [ 1726.919494] RIP [<ffffffff81151821>] nfs_clear_request_commit+0x11/0x90 Apr 5 19:53:59 thoregon kernel: [ 1726.919522] RSP <ffff8801e546fb08> Apr 5 19:53:59 thoregon kernel: [ 1726.919537] CR2: 0000000000000048 Apr 5 19:53:59 thoregon kernel: [ 1726.940636] ---[ end trace 0e47a071a9891fab ]--- Otherwise 3.4-rc1 works fine for me. And other big downloads before and after that worked fine. (gdb) list *0xffffffff81151821 0xffffffff81151821 is in nfs_clear_request_commit (/usr/src/linux-3.4-rc1/arch/x86/include/asm/bitops.h:312). 307 } 308 309 static __always_inline int constant_test_bit(unsigned int nr, const volatile unsigned long *addr) 310 { 311 return ((1UL << (nr % BITS_PER_LONG)) & 312 (addr[nr / BITS_PER_LONG])) != 0; 313 } 314 315 static inline int variable_test_bit(int nr, volatile const unsigned long *addr) 316 { (gdb) list *0xffffffff81152d98 0xffffffff81152d98 is in nfs_updatepage (fs/nfs/write.c:685). 680 req->wb_bytes = end - req->wb_offset; 681 else 682 req->wb_bytes = rqend - req->wb_offset; 683 out_unlock: 684 spin_unlock(&inode->i_lock); 685 nfs_clear_request_commit(req); 686 return req; 687 out_flushme: 688 spin_unlock(&inode->i_lock); 689 nfs_release_request(req); Thanks for looking into this. Torsten -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html