I have a new module that uses the async_tx.h lib.
On an exact same module code based on 3.6.37 I see the:
xor: measuring software checksum speed
8regs : 11312.000 MB/sec
8regs_prefetch: 9792.800 MB/sec
32regs : 11220.400 MB/sec
32regs_prefetch: 9750.800 MB/sec
xor: using function: 8regs (11312.000 MB/sec)
And all is well. But on code based on 2.6.38-rc4 I get hard stuck
right after:
xor: measuring software checksum speed
the UML is completely frozen. When I kill the uml from the host
I can sometimes get this trace.
750c7498: [<6005f936>] bad_page+0xd8/0xf3
750c74c8: [<60060c93>] get_page_from_freelist+0x333/0x47b
750c7508: [<60131243>] put_dec+0x20/0x3c
750c75a0: [<6001a0ac>] change_pre_exec+0x0/0x24
750c75b8: [<60060ef1>] __alloc_pages_nodemask+0x116/0x65b
750c7668: [<60132e25>] sprintf+0xa1/0xa3
750c76a0: [<6001a0ac>] change_pre_exec+0x0/0x24
750c76b8: [<60061446>] __get_free_pages+0x10/0x43
750c76c8: [<60012875>] alloc_stack+0x1b/0x1d
750c76d8: [<6001fe27>] run_helper+0x26/0x1b5
750c76e8: [<60021553>] set_signals+0x1c/0x2e
750c7708: [<6007efac>] __kmalloc+0x9e/0xc4
750c7748: [<6001a544>] change+0x124/0x189
750c77e8: [<601b77db>] _raw_spin_unlock+0x9/0xb
750c7818: [<6001a5a9>] close_addr+0x0/0x1c
750c7828: [<6001a5c3>] close_addr+0x1a/0x1c
750c7838: [<6001926a>] iter_addresses+0x5f/0x76
750c7858: [<6007e8e8>] kfree+0x92/0x9b
750c7898: [<60022d01>] tuntap_close+0x24/0x38
750c78b8: [<600194e4>] close_devices+0x4a/0x7f
750c78d8: [<600121bf>] do_uml_exitcalls+0x12/0x23
750c78f8: [<60012cd2>] uml_cleanup+0x1a/0x87
750c7928: [<6002039b>] last_ditch_exit+0x9/0x16
750c79e8: [<78817031>] xor_8regs_2+0x31/0x58 [xor]
750c7a18: [<7881b000>] calibrate_xor_blocks+0x0/0xdf [xor]
750c7aa8: [<601b77ce>] _raw_spin_unlock_irqrestore+0x18/0x1c
750c7ac8: [<60029d8d>] try_to_wake_up+0x86/0x98
750c7d78: [<601b548d>] printk+0xa0/0xa3
750c7e08: [<78817633>] do_xor_speed+0x54/0xaf [xor]
750c7e20: [<7881b000>] calibrate_xor_blocks+0x0/0xdf [xor]
750c7e58: [<7881b057>] calibrate_xor_blocks+0x57/0xdf [xor]
750c7e68: [<7881b000>] calibrate_xor_blocks+0x0/0xdf [xor]
750c7e78: [<6001105a>] do_one_initcall+0x76/0x121
750c7eb8: [<600563fd>] sys_init_module+0x78/0x1a6
750c7ee8: [<60014d60>] handle_syscall+0x58/0x70
750c7f08: [<60024163>] userspace+0x2dd/0x38a
750c7fc8: [<600126af>] fork_handler+0x62/0x69
(gdb) list *(xor_8regs_2+0x31)
0x55 is in xor_8regs_2
(/usr0/export/dev/bharrosh/git/pub/scsi-misc/include/asm-generic/xor.h:29).
24 p1[0] ^= p2[0];
25 p1[1] ^= p2[1];
26 p1[2] ^= p2[2];
27 p1[3] ^= p2[3];
28 p1[4] ^= p2[4];
29 p1[5] ^= p2[5];
30 p1[6] ^= p2[6];
31 p1[7] ^= p2[7];
32 p1 += 8;
33 p2 += 8;
(gdb) list *(calibrate_xor_blocks+0x0)
0xd52 is in calibrate_xor_blocks
(/usr0/export/dev/bharrosh/git/pub/scsi-misc/crypto/xor.c:101).
96 speed / 1000, speed % 1000);
97 }
98
99 static int __init
100 calibrate_xor_blocks(void)
101 {
102 void *b1, *b2;
103 struct xor_block_template *f, *fastest;
104
105 /*
(gdb) list *(do_xor_speed+0x54)
0x657 is in do_xor_speed
(/usr0/export/dev/bharrosh/git/pub/scsi-misc/crypto/xor.c:84).
79 now = jiffies;
80 count = 0;
81 while (jiffies == now) {
82 mb(); /* prevent loop optimzation */
83 tmpl->do_2(BENCH_SIZE, b1, b2);
84 mb();
85 count++;
86 mb();
87 }
88 if (count > max)
(gdb) list *(calibrate_xor_blocks+0x57)
0xda9 is in calibrate_xor_blocks
(/usr0/export/dev/bharrosh/git/pub/scsi-misc/crypto/xor.c:137).
132 "checksumming function: %s\n",
133 fastest->name);
134 xor_speed(fastest);
135 } else {
136 printk(KERN_INFO "xor: measuring software checksum
speed\n");
137 XOR_TRY_TEMPLATES;
138 fastest = template_list;
139 for (f = fastest; f; f = f->next)
140 if (f->speed > fastest->speed)
141 fastest = f;
(gdb) q
So it looks like the code in UML links the include/asm-generic/xor.h and that
it gets
stuck. Any thing changed in this area in last merge window?
Before I start the very difficult bisect?
Thanks for any tips
Boaz
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