Bug 11758
| Summary: | a program's data segment grows beyond RLIMIT_DATA limit set by setrlimit | ||
|---|---|---|---|
| Product: | Memory Management | Reporter: | L. Nieroda (lnieroda) |
| Component: | Other | Assignee: | Andrew Morton (akpm) |
| Status: | CLOSED OBSOLETE | ||
| Severity: | normal | CC: | alan, david.w.h.chin, fion2009.z, matt |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.27 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: |
mmap.c class where we change rlimit data condition
task_mmu.c for data limit |
||
(In reply to comment #0) I found this, it might help http://marc.info/?l=linux-kernel&m=118064795330579&w=2 > Latest working kernel version: N/A > Earliest failing kernel version: N/A > Distribution: Ubuntu > Hardware Environment: Intel CoreDuo E8400, 4 GB RAM > Software Environment: Ubuntu 8.04 > Problem Description: I'm setting RLIMIT_DATA with the setrlimit system call > and > then proceed to allocate memory with malloc or "new" grossly above that > limit, > however, the memory is allocated and used without a problem. I've tried this > with and without swap to make sure that the memory isn't allocated within it. > The same check with RLIMIT_AS returns the expected result: memory allocation > error. Am I missing something? > > Steps to reproduce: > I've made a small c program to reproduce this behaviour: > > --- > #include <stdio.h> > #include <sys/resource.h> > #include <errno.h> > > > #define SOFT_LIMIT 100000 > #define HARD_LIMIT 100000 > #define ALLOCATED 150000 > > void check_rlimit(int resource) { > char *data = NULL; > struct rlimit rlp; > > rlp.rlim_cur = SOFT_LIMIT; rlp.rlim_max=HARD_LIMIT; > > //setting the limits > if (setrlimit(resource, &rlp) == -1) { > perror("setrlimit"); > exit(1); > } > > //check if limits are set > if (getrlimit(resource, &rlp) == -1) { > perror("getrlimit"); > exit(1); > } > > printf("softlimit: %d \n", rlp.rlim_cur); > printf("hardlimit: %d \n", rlp.rlim_max); > > fflush(stdout); > > //allocate over the limit > printf("Allocating %d bytes.\n",ALLOCATED); > data = (char *)malloc(ALLOCATED); > if (data == NULL) { > //printf("malloc failed with errno=%d\n", errno); > perror("malloc"); > exit(1); > } > free(data); > } > > int main(int argc, char *argv[]) { > > check_rlimit(RLIMIT_DATA); > check_rlimit(RLIMIT_AS); > > return 0; > exit(0); > } > --- > > The output is: > softlimit: 100000 > hardlimit: 100000 > Allocating 150000 bytes. > softlimit: 100000 > hardlimit: 100000 > Allocating 150000 bytes. > malloc: Cannot allocate memory > > Any ideas? > > Regards, > Lech Nieroda > Yep, when brk fails because of RLIMIT_DATA, glibc switches to anonymous mmap instead. https://bugzilla.redhat.com/show_bug.cgi?id=569714 http://lists.fedoraproject.org/pipermail/users/2010-March/368014.html Same issue (reported by Matt McCutchen) being tracked on Fedora/RedHat's bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=582072 Created attachment 54912 [details]
mmap.c class where we change rlimit data condition
Hi,
Yes We got same issue on linux kernel 2.6.32.29. We identified solution by doing some changes in files: mmap.c and task_mmu.c which are attached here. Basically we modify conditions regarding private memory of process(rlimit). We shall upload patch soon. Please find attached file, you can replace these files and compile your kernel and once you done it will will not show you this bug any more.
Thanks
Waseem Hassan
Saad Waqas
Created attachment 54922 [details]
task_mmu.c for data limit
Yes, we'd need to see the patch, not the whole files. Please send the patch via email, not via bugzilla. Send it as a proper patch as per Documentation/SubmittingPatches. Send it to Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org Thanks. |
Latest working kernel version: N/A Earliest failing kernel version: N/A Distribution: Ubuntu Hardware Environment: Intel CoreDuo E8400, 4 GB RAM Software Environment: Ubuntu 8.04 Problem Description: I'm setting RLIMIT_DATA with the setrlimit system call and then proceed to allocate memory with malloc or "new" grossly above that limit, however, the memory is allocated and used without a problem. I've tried this with and without swap to make sure that the memory isn't allocated within it. The same check with RLIMIT_AS returns the expected result: memory allocation error. Am I missing something? Steps to reproduce: I've made a small c program to reproduce this behaviour: --- #include <stdio.h> #include <sys/resource.h> #include <errno.h> #define SOFT_LIMIT 100000 #define HARD_LIMIT 100000 #define ALLOCATED 150000 void check_rlimit(int resource) { char *data = NULL; struct rlimit rlp; rlp.rlim_cur = SOFT_LIMIT; rlp.rlim_max=HARD_LIMIT; //setting the limits if (setrlimit(resource, &rlp) == -1) { perror("setrlimit"); exit(1); } //check if limits are set if (getrlimit(resource, &rlp) == -1) { perror("getrlimit"); exit(1); } printf("softlimit: %d \n", rlp.rlim_cur); printf("hardlimit: %d \n", rlp.rlim_max); fflush(stdout); //allocate over the limit printf("Allocating %d bytes.\n",ALLOCATED); data = (char *)malloc(ALLOCATED); if (data == NULL) { //printf("malloc failed with errno=%d\n", errno); perror("malloc"); exit(1); } free(data); } int main(int argc, char *argv[]) { check_rlimit(RLIMIT_DATA); check_rlimit(RLIMIT_AS); return 0; exit(0); } --- The output is: softlimit: 100000 hardlimit: 100000 Allocating 150000 bytes. softlimit: 100000 hardlimit: 100000 Allocating 150000 bytes. malloc: Cannot allocate memory Any ideas? Regards, Lech Nieroda