Satyam Sharma wrote: > Hi Gabriel, > > On 7/16/07, Gabriel C <[EMAIL PROTECTED]> wrote: > > >> ( http://194.231.229.228/Oops.txt ) >> > > >> I cannot reproduce this on plain 2.6.22 so I've started to bisect the >> problem. >> > > Could you reproduce this oops at will at the "bad" points? [ Note that > git-bisect isn't quite applicable to bugs that are not 100% reproducible. > The ones that passed as "good" may have passed only because the > bug didn't get triggered on that particular test. Also, a perfectly good > commit could get unnecessarily marked "bad" because the bug > happened to get triggered for it ... so it's not quite trust-worthy for > your case. ] >
Yes all marked 'bad' ponts have the Oops , at least here. > >> Here the bisect result: >> >> 3007e997de91ec59af39a3f9c91595b31ae6e08b is first bad commit >> commit 3007e997de91ec59af39a3f9c91595b31ae6e08b >> Author: Tejun Heo <[EMAIL PROTECTED]> >> Date: Thu Jun 14 04:27:23 2007 +0900 >> >> sysfs: use sysfs_mutex to protect the sysfs_dirent tree >> >> As kobj sysfs dentries and inodes are gonna be made reclaimable, >> i_mutex can't be used to protect sysfs_dirent tree. Use sysfs_mutex >> globally instead. As the whole tree is protected with sysfs_mutex, >> there is no reason to keep sysfs_rename_sem. Drop it. >> >> While at it, add docbook comments to functions which require >> sysfs_mutex locking. >> >> Signed-off-by: Tejun Heo <[EMAIL PROTECTED]> >> Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]> >> >> :040000 040000 9deba7887752bc343cc4f5dea2dac70e895ea8b6 >> 75340b6e18c1ada500bb1a2b99ee88fd93ebae8c M fs >> > > Hmm, I don't see why this one could introduce an oops in SLUB, > but it's doing some locking-related stuff, and if it didn't get it right, > the resulting races /could/ lead to some oops. But ... a recently > posted patch (http://lkml.org/lkml/2007/7/16/204) from Akinobu > Mita does point to an oops that was introduced by commit > 0c096b507f15397da890051ee73de4266d3941fb that belongs to the > same patchset -- kmem_cache_free(NULL) is illegal and so will oops. > A curious coincidence is that you do see sysfs_new_dirent() in the > stack trace there, but the oops there is in kmem_cache_free(), not > kmem_cache_zalloc() as your dmesg output indicated. > > Try that patch anyway, but I don't think that'll solve your problem -- > if it was, you would've been seeing "unable to handle kernel NULL > pointer dereference" but what you've been posting is "unable to > handle kernel paging request at virtual address <non_null_ptr>" ... > I will try this patch and look whatever it helps. > Gaah. > > And the worst thing about it all is that we're not able to trigger the > oops with debugging options -- that backtrace is horrible, so I'd > suggest CONFIG_FRAME_POINTER, at the very least. And also > perhaps DEBUG_INFO while we're at it -- that'll make later > analysis easier, if nothing else. > I will enable DEBUG option and reproduce in a bit. > [ BTW I couldn't even get my compiler to generate the same > "Code:" as we saw in your dmesg (I suspect all the oopsen > have occurred with DEBUG=n, yes?) so my earlier analysis > that suspected SLUB's page->lockless_freelist in slab_alloc() > as the source of that invalid kernel address was actually > based on some human-work rather than simple tools doing > their thing. Gaah, again! ] > My original report ( also first Oops posted here ) was with DEBUG_KERNEL=y but as I said I will reproduce in a bit with all the DEBUG options you suggested. Shall I enable DEBUG_PAGEALLOC too ? > I'm thoroughly mystified ... Christoph? Tejun? Someone? > > Satyam > > Gabriel - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
