On Thu, 26 Feb 2009 09:45:41 am Mark Nelson wrote: > On Thu, 26 Feb 2009 12:31:20 am Geert Uytterhoeven wrote: > > On Wed, 25 Feb 2009, Mark Nelson wrote: > > > On Wed, 25 Feb 2009 08:50:46 pm Geert Uytterhoeven wrote: > > > > On Wed, 25 Feb 2009, Mark Nelson wrote: > > > > > On Tue, 24 Feb 2009 05:38:37 pm Sachin P. Sant wrote: > > > > > > Jan Kara wrote: > > > > > > > Hmm, OK. But then I'm not sure how that can happen. Obviously, memcpy > > > > > > > somehow got beyond end of the page referenced by bh->b_data. So it means > > > > > > > that le16_to_cpu(entry->e_value_offs) + size > page_size. But > > > > > > > ext3_xattr_find_entry() calls ext3_xattr_check_entry() which in > > > > > > > particular checks whether e_value_offs + e_value_size isn't greater than > > > > > > > bh->b_size. So I see no way how memcpy can get beyond end of the page. > > > > > > > Sachin, is the problem reproducible? If yes, can you send us contents > > > > > > > > > > > > > Yes, i am able to recreate this problem easily. As i had mentioned if the > > > > > > earlier kernel is booted with selinux enabled and then 2.6.29-rc6 is booted > > > > > > i get this crash. But if i specify selinux=0 at command line, 2.6.29-rc6 boots > > > > > > without any problem. > > > > > > > > > > Hi Sanchin and Geert, > > > > > > > > > > Does the patch below fix the problems you're seeing? If it does I'll send > > > > > a properly written up and formatted patch to linuxppc-dev (as well as > > > > > another one to fix the same problem in copy_tofrom_user()). > > > > > > > > Unfortunately not, now it crashes while accessing the memory pointed to by > > > > GPR16, in > > > > > > > > NIP: copy_page_range+x0608/0x628 > > > > LR: dup_mm+0x2e4/0x428 > > > > Trace: debug_table+0xcc70/0x1afe0 (unreliable) > > > > dup_mm+0x2e4/0x428 > > > > copy_process+0x86c/0xf9c > > > > do_fork+0x188/0x39c > > > > sys_clone+0x58/0x70 > > > > ppc_clone+0x8/0xc > > > > > > > > However, after reverting 25d6e2d7c58ddc4a3b614fc5381591c0cfe66556, I still see > > > > similar problems as above (crash in copy_page_range()). > > > > Which makes me think that > > > > 1. Your new patch fixes the problem introduced by 25d6e2d7, > > > > 2. There's still another issue than the one introduced by 25d6e2d7. > > > > > > Does the following patch fix the errors you're seeing? (it applies the > > > same fix as the previous patch but this time to copy_tofrom_user, which > > > I updated in a4e22f02f5b6518c1484faea1f88d81802b9feac) > > > > Thanks, but I still get crashes in copy_page_range(). > > > > Hmmm... I'm out of ideas for the moment, but thanks for testing anyway! > > Mark > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@xxxxxxxxxx > https://ozlabs.org/mailman/listinfo/linuxppc-dev > If you revert both 25d6e2d7c58ddc4a3b614fc5381591c0cfe66556 and a4e22f02f5b6518c1484faea1f88d81802b9feac, does it help? You could also try to revert 57dda6ef5bd5b9e60410477ad29e654097e2cca1 just in case I need to keep wearing the brown paper bag for a bit longer :) Thanks! Mark -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
