157 class global_rand_permute_workload: public workload_gen
158 {
159 long start;
160 long end;
161 static const rand_permute *permute;
162 public:
163 global_rand_permute_workload(long num, int stride, long start, long
end) {
164 if (permute == NULL) {
165 permute = new rand_permute(num, stride);
166 }
167 this->start = start;
168 this->end = end;
169 }
In rand-read.cc,
300 int entry_size = 128;
399 int num_entries = npages * (PAGE_SIZE / entry_size);
473 case RAND_PERMUTE:
474 gen = new global_rand_permute_workload(num_entries,
475 entry_size, start, end);
npages is also initialized. Every variable should have been initialized. I
don't know where the problem is.
Thanks,
Da
476 break;
On Sat, May 5, 2012 at 2:38 PM, Geoff Alexander <[email protected]>wrote:
> Da,****
>
> ** ******
>
> You don’t show the code that’s calling rand_permute::rand_permute(long,
> int). In particular, the passed in value of stride could be
> uninitialized.****
>
> ** ******
>
> Geoff****
>
> ** ******
>
> -----Original Message-----
> *From:* Zheng Da [mailto:[email protected]]
> *Sent:* Saturday, May 05, 2012 2:26 PM
> *To:* Philippe Waroquiers
> *Cc:* [email protected]
> *Subject:* Re: [Valgrind-users] valgrind prints out a lot of error
> messages pointing to the standard library
>
> ** ******
>
> hello,****
>
> > ==32701== Conditional jump or move depends on uninitialised value(s)
> > ==32701== at 0x4FB3D9: fillin_rpath
> > (in /home/zhengda/Dropbox/research/read-test/rand-read)
> > ==32701== by 0x4FDBCB: _dl_init_paths
> > (in /home/zhengda/Dropbox/research/read-test/rand-read)
> > ==32701== by 0x4CCC58: _dl_non_dynamic_init
> > (in /home/zhengda/Dropbox/research/read-test/rand-read)
> > ==32701== by 0x4CD762: __libc_init_first
> > (in /home/zhengda/Dropbox/research/read-test/rand-read)
> > ==32701== by 0x47F795: (below main)
> > (in /home/zhengda/Dropbox/research/read-test/rand-read)
> > ==32701==****
>
> The above error for example looks to somewhat match a suppression in
> glibc-2.3.supp
>
> It is however not clear what is the cause of all these errors
> not being suppressed.
> Note that usually, having more info such as Valgrind version,
> OS and distribution version, cpu etc might only help to guess
> what it is :).****
>
> Sorry, I forget.****
>
> I use valgrind-3.6.1, ****
>
> ubuntu 11.04, ****
>
> Xeon(R) CPU E5405****
>
> Linux 2.6.38.8****
>
> ** ******
>
> Other than the errors in the standard library, it also shows many errors
> in my own program and I found the error messages are also very misleading.
> ****
>
> ** ******
>
> ==21746== Use of uninitialised value of size 8****
>
> ==21746== at 0x40D168: rand_permute::rand_permute(long, int)
> (workload.h:63)****
>
> ==21746== by 0x410624:
> global_rand_permute_workload::global_rand_permute_workload(long, int, long,
> long) (workload.h:165)****
>
> ==21746== by 0x40F3FD: main (rand-read.cc:475)****
>
> ==21746== ****
>
> ** ******
>
> The corresponding code is shown below. I don't understand which variable
> isn't initialized?****
>
> ** ******
>
> 54 class rand_permute****
>
> 55 {****
>
> 56 off_t *offset;****
>
> 57 long num;****
>
> 58 ****
>
> 59 public:****
>
> 60 rand_permute(long num, int stride) {****
>
> 61 offset = (off_t *) valloc(num * sizeof(off_t));****
>
> 62 for (int i = 0; i < num; i++) {****
>
> 63 offset[i] = ((off_t) i) * stride;****
>
> 64 }****
>
> 65 ****
>
> 66 for (int i = num - 1; i >= 1; i--) {****
>
> 67 int j = random() % i;****
>
> 68 off_t tmp = offset[j];****
>
> 69 offset[j] = offset[i];****
>
> 70 offset[i] = tmp;****
>
> 71 }****
>
> 72 }****
>
> ** ******
>
> Thanks,****
>
> Da****
>
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