On Thu, 2009-08-06 at 21:39 +0530, naresh kamboju wrote: > Hi, > > In addition to the below Link discussion > > Date: 16 Jul 2009 > http://www.mail-archive.com/[email protected]/msg07506.html > > patch is not yet committed to LTP CVs.
I am a bit perplexed by all these links. Can you please RESEND the concerned patch with the required description. I would then check that in. Regards-- Subrata > > as per test case Description > > /*****************************************************/ > * Implementation performs mapping operations over whole pages. > * Thus, while the argument len > * need not meet a size or alignment constraint, > * the implementation shall include, in any mapping > * operation, any partial page specified by the range [pa,pa+len). > * The system shall always zero-fill any partial page at the end of an object. > * Further, the system shall never write out any modified portions of > * the last page of an object which are beyond its end. > * > * Test step: > * 1. Create a process, in this process: > a. map a file with size of 1/2 * page_size, > * set len = 1/2 * page_size > * b. Read the partial page beyond the object size. > * Make sure the partial page is zero-filled; > * c. Modify a byte in the partial page, then un-map the and close the > * file descriptor. > * 2. Wait for the child proces to exit, then > * Map the file again, > * read the byte from the position modified at step 1-c and check. > */ > /****************************************************/ > > please note the below discussion > > http://bugs.gentoo.org/197191 > > Ref: > http://www.opengroup.org/onlinepubs/009695399/functions/mmap.html > > fan he, > > please make sure who is going to do this is it coming from kernel or glibc? > > Best regards > Naresh Kamboju > > > >On Mon, 2009-07-20 at 00:46 -0700, Garrett Cooper wrote: > > On Sun, Jul 19, 2009 at 10:54 PM, Michal > > Simek<[email protected]> wrote: > > > Hi, > > >> On Sat, 2009-07-18 at 12:28 -0700, Garrett Cooper wrote: > > >> > > >>> On Thu, Jul 16, 2009 at 11:37 PM, hefan<[email protected]> wrote: > > >>> > > >>>> hi, > > >>>> > > >>>> *[Patch 1/1] Patch for fixing the failed testcase openposix_mmap_11_4 > > >>>> > > >>>> -modified the file > > >>>> *testcases/open_posix_testsuite/conformance/interfaces/mmap/11-4.c > > > > > > First of all - this is really small explanation why you are fixing this > > > issue. After some month > > > none will know why you did this change. > > > > > > > > >>>> > > >>>> Signed-off-by: fredrick he <[email protected]> > > >>>> > > >>>> --- > > >>>> ltp.orig/testcases/open_posix_testsuite/conformance/interfaces/mmap/11-4.c > > >>>> 2009-07-17 11:53:36.000000000 +0800 > > >>>> +++ > > >>>> ltp/testcases/open_posix_testsuite/conformance/interfaces/mmap/11-4.c > > >>>> 2009-07-17 11:57:09.000000000 +0800 > > >>>> @@ -130,7 +130,9 @@ int main() > > >>>> flag = MAP_SHARED; > > >>>> off = 0; > > >>>> pa = mmap(addr, len, prot, flag, fd_2, off); > > >>>> - pa_2 = mmap(addr, len, prot, flag, fd_2, off); > > >>>> + addr = pa; > > >>>> + memset(addr,0,len*2); > > >>>> + pa_2 = mmap(addr, len, prot, flag|MAP_FIXED, fd_2, off); > > >>>> if (pa_2 == MAP_FAILED) > > >>>> { > > >>>> printf("Test FAIL: " TNAME " Error at 2nd mmap(): %s\n", > > >>>> > > >>> Hi Fan, > > >>> Some questions / observations: > > >>> > > >>> 1. Yes, the testcases does fail on my machine today. > > >>> 2. Yes, doing what you say above does work (at least the testcase > > >>> passes). > > >>> 3. Are you positive that your set of steps above in fact don't > > >>> invalidate the purpose of the testcase, by accident, in particular the > > >>> memset call? I ask because of the following statement in the mmap > > >>> manpage: > > >>> > > >>> If addr is NULL, then the kernel chooses the address at which to > > >>> create > > >>> the mapping; this is the most portable method of creating a new > > >>> map- > > >>> ping. If addr is not NULL, then the kernel takes it as a hint > > >>> about > > >>> where to place the mapping; on Linux, the mapping will be created > > >>> at a > > >>> nearby page boundary. The address of the new mapping is > > >>> returned as > > >>> the result of the call. > > >>> > > >>> What you're in effect doing is changing the 2nd mmap call from an > > >>> arbitrary address to a set virtual address at 0x0. Is that indeed > > >>> correct? > > >>> > > >> in this case, the situation is like this, we create a new file about 512 > > >> bytes and mmap it into the mem, then we modify one byte besides the 512 > > >> bytes address, and munmap it. and in the father process remmap it back > > >> to check whether the one more byte is write back to the files. > > > > Ok. > > > > >> i have checked that when finished munmap and close the file in the child > > >> process, the file didn't contain the 513th byte, the size of this file > > >> is right 512 bytes.but in this case after the second mmap finished, the > > >> 513th byte does appear again. it's a conflict. > > >> > > >> in my opinion this is because of the compiler or some optimizations. so > > >> i think the memory should to be memset before mmap and it does work. > > > > No, according to the manpage it'll map to the boundary of the closest > > page size, in my opinion what might be occurring is the system is > > either overallocating or underallocating, depending on the system page > > size and what's being passed in for a length. What the page size is, > > I'd surely like to know... > here in my environment the page size is 1024 got by using > sysconf(_SC_PAGE_SIZE) in this testcase > > > > > If is the problem with compiler/optimization means that tests is ok - > > > the problem is with your > > > compiler not with code. > > > This need more investigations to find out where the problem is. > > > > I wouldn't necessarily say that. Based on Frederick's explanation, it > > sounds like someone fed in an inappropriate bound, or didn't NUL > > terminate the boundary and just went off into uncharted territory > > without first checking where they were `on the map'. > > > > Based on my experience and recollection, this is legitimate in C > > behavior as long as you're within the applications memory limits -- > > you've just entered the twilight zone between realities, where you're > > beyond your address space, but not beyond the point of no return > > (EACCES), where the kernel *should* terminate your userland app. > >yeah, that's the keypoint. but it doesn't terminate our userland app. > > >i mean that here is a mistake on the way this testcase check the result. > >ideally, the mmap should only use half a page and it has no > >resposibility on the rest of the page, so we shouldn't judge the mmap by > >the rest of the page which is none of business with mmap. > > >so if we suppose that the mmap does affect the rest of the page( is it > >the purpose to design this testcase ? ), we should make sure that this > >area has been clear before we mmap the file into this area. that's why i > >use memset and flag MAP_FIXED. > > > > > Whether or not that was the intention of the POSIX folks, is another > > question indeed, as the documentation states (in the header of the .c > > file): > > > > * Implementation performs mapping operations over whole pages. > > * Thus, while the argument len > > * need not meet a size or alignment constraint, > > * the implementation shall include, in any mapping > > * operation, any partial page specified by the range [pa,pa+len). > > * The system shall always zero-fill any partial page at the end of an > > object. > > * Further, the system shall never write out any modified portions of > > * the last page of an object which are beyond its end. > > > > So unless they're completely misinterpreting the meaning of mmap, it > > sounds like there's a bug in a number of `POSIX-compliant' operating > > systems that needs to be resolved (FreeBSD and Linux included). > > > > However, before jumping to conclusions, I think that it's prudent to > > narrow down where and why this is occurring... > > > > >>> 4. Have you talked to the openposix test suite folks about this yet? > > >>> > > >> no,i have no idea on how to talk to the openposix and i do want to talk > > >> to them :) can you give me some suggestions about this? thx~ > > > > The project administrators are available, as noted, here: > > > > https://sourceforge.net/project/memberlist.php?group_id=64592 > > > > Thanks, > > -Garrett ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Ltp-list mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ltp-list
