| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Tue, 6 Apr 2010 13:02:35 -0700 (PDT) From: Linus Torvalds <torvalds@...ux-foundation.org> To: Borislav Petkov <bp@...en8.de> cc: Andrew Morton <akpm@...ux-foundation.org>, Rik van Riel <riel@...hat.com>, Minchan Kim <minchan.kim@...il.com>, KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Lee Schermerhorn <Lee.Schermerhorn@...com>, Nick Piggin <npiggin@...e.de>, Andrea Arcangeli <aarcange@...hat.com>, Hugh Dickins <hugh.dickins@...cali.co.uk>, sgunderson@...foot.com Subject: Re: Ugly rmap NULL ptr deref oopsie on hibernate (was Linux 2.6.34-rc3) On Tue, 6 Apr 2010, Borislav Petkov wrote: > > [ 2995.478125] PM: Preallocating image memory... > [ 2995.713692] BUG: unable to handle kernel NULL pointer dereference at (null) > [ 2995.714001] IP: [<ffffffff810c194d>] page_referenced+0xee/0x1dc > [ 2995.714001] PGD 22d1b8067 PUD 22dd85067 PMD 0 > [ 2995.714001] Oops: 0000 [#1] PREEMPT SMP > [ 2995.714001] last sysfs file: /sys/power/state > [ 2995.714001] CPU 0 > [ 2995.714001] Modules linked in: tun powernow_k8 cpufreq_ondemand cpufreq_powersave cpufreq_userspace freq_table cpufreq_conservative binfmt_misc kvm_amd kvm ipv6 vfat fat dm_crypt dm_mod ohci_hcd pcspkr 8250_pnp 8250 k10temp edac_core serial_core > [ 2995.714001] > [ 2995.714001] Pid: 7440, comm: hib.sh Not tainted 2.6.34-rc3-00288-gab195c5 #1 M3A78 PRO/System Product Name > [ 2995.714001] RIP: 0010:[<ffffffff810c194d>] [<ffffffff810c194d>] page_referenced+0xee/0x1dc > [ 2995.714001] RSP: 0018:ffff88022fa038b8 EFLAGS: 00010283 > [ 2995.714001] RAX: ffff88022d747098 RBX: ffffea00078efb70 RCX: 0000000000000000 > [ 2995.714001] RDX: ffff88022fa03cf8 RSI: ffff88022d747070 RDI: ffff88022fb32520 > [ 2995.714001] RBP: ffff88022fa03938 R08: 0000000000000002 R09: 0000000000000000 > [ 2995.714001] R10: ffff88022fa038a8 R11: ffff88022d295d10 R12: 0000000000000000 > [ 2995.714001] R13: ffffffffffffffe0 R14: ffff88022d747058 R15: ffff88022fa03a00 > [ 2995.714001] FS: 00007f4da8b966f0(0000) GS:ffff88000a000000(0000) knlGS:0000000000000000 > [ 2995.714001] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 2995.714001] CR2: 0000000000000000 CR3: 000000022d11e000 CR4: 00000000000006f0 > [ 2995.714001] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 2995.714001] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > [ 2995.714001] Process hib.sh (pid: 7440, threadinfo ffff88022fa02000, task ffff88022fb32520) > [ 2995.714001] Stack: > [ 2995.714001] ffff88022d747098 00000000813fd2ac ffffffff8165ee28 0000000000000416 > [ 2995.714001] <0> ffff88022fa038f8 ffffffff810c6d40 ffffea00078fae60 ffffea00078fae60 > [ 2995.714001] <0> ffff88022fa03938 00000002810abd98 ffffea00078ec530 ffffea00078efb98 > [ 2995.714001] Call Trace: > [ 2995.714001] [<ffffffff810c6d40>] ? swapcache_free+0x37/0x3c > [ 2995.714001] [<ffffffff810ac31d>] shrink_page_list+0x171/0x4b1 > [ 2995.714001] [<ffffffff813fd1e6>] ? _raw_spin_unlock_irq+0x30/0x58 > [ 2995.714001] [<ffffffff810ac9b9>] shrink_inactive_list+0x35c/0x623 > [ 2995.714001] [<ffffffff810acd94>] ? shrink_zone+0x114/0x3d4 > [ 2995.714001] [<ffffffff81064f29>] ? print_lock_contention_bug+0x1b/0xe1 > [ 2995.714001] [<ffffffff813fc790>] ? _raw_spin_lock_irq+0x19/0x79 > [ 2995.714001] [<ffffffff810acf8a>] shrink_zone+0x30a/0x3d4 > [ 2995.714001] [<ffffffff810ad19e>] ? shrink_slab+0x14a/0x15c > [ 2995.714001] [<ffffffff810adb65>] do_try_to_free_pages+0x176/0x27f > [ 2995.714001] [<ffffffff8103de67>] ? irq_exit+0x93/0x95 > [ 2995.714001] [<ffffffff810add03>] shrink_all_memory+0x95/0xc4 > [ 2995.714001] [<ffffffff810ab0f0>] ? isolate_pages_global+0x0/0x217 > [ 2995.714001] [<ffffffff81077503>] ? count_data_pages+0x65/0x79 > [ 2995.714001] [<ffffffff8107776a>] hibernate_preallocate_memory+0x1aa/0x2cb > [ 2995.714001] [<ffffffff813f95b5>] ? printk+0x41/0x44 > [ 2995.714001] [<ffffffff810760b3>] hibernation_snapshot+0x36/0x1e1 > [ 2995.714001] [<ffffffff8107632c>] hibernate+0xce/0x172 > [ 2995.714001] [<ffffffff81075099>] state_store+0x5c/0xd3 > [ 2995.714001] [<ffffffff8118728f>] kobj_attr_store+0x17/0x19 > [ 2995.714001] [<ffffffff81127b69>] sysfs_write_file+0x108/0x144 > [ 2995.714001] [<ffffffff810d66ff>] vfs_write+0xb2/0x153 > [ 2995.714001] [<ffffffff810641a9>] ? trace_hardirqs_on_caller+0x1f/0x14b > [ 2995.714001] [<ffffffff810d6863>] sys_write+0x4a/0x71 > [ 2995.714001] [<ffffffff810021db>] system_call_fastpath+0x16/0x1b > [ 2995.714001] Code: 3b 56 10 73 1e 48 83 fa f2 74 18 48 8d 4d cc 4d 89 f8 48 89 df e8 4d f2 ff ff 41 01 c4 83 7d cc 00 74 19 4d 8b 6d 20 49 83 ed 20 <49> 8b 45 20 0f 18 08 49 8d 45 20 48 39 45 80 75 aa 4c 89 f7 e8 > [ 2995.714001] RIP [<ffffffff810c194d>] page_referenced+0xee/0x1dc > [ 2995.714001] RSP <ffff88022fa038b8> > [ 2995.714001] CR2: 0000000000000000 > [ 2995.729717] ---[ end trace 92c25d74e4800968 ]--- So again, I can show that the code has never actually been through the loop. The above code decodes to: 0: 3b 56 10 cmp 0x10(%rsi),%edx 3: 73 1e jae 0x23 5: 48 83 fa f2 cmp $0xfffffffffffffff2,%rdx 9: 74 18 je 0x23 b: 48 8d 4d cc lea -0x34(%rbp),%rcx f: 4d 89 f8 mov %r15,%r8 12: 48 89 df mov %rbx,%rdi 15: e8 4d f2 ff ff callq 0xfffffffffffff267 1a: 41 01 c4 add %eax,%r12d 1d: 83 7d cc 00 cmpl $0x0,-0x34(%rbp) 21: 74 19 je 0x3c 23: 4d 8b 6d 20 mov 0x20(%r13),%r13 27: 49 83 ed 20 sub $0x20,%r13 2b:* 49 8b 45 20 mov 0x20(%r13),%rax <-- trapping instruction 2f: 0f 18 08 prefetcht0 (%rax) 32: 49 8d 45 20 lea 0x20(%r13),%rax 36: 48 39 45 80 cmp %rax,-0x80(%rbp) 3a: 75 aa jne 0xffffffffffffffe6 3c: 4c 89 f7 mov %r14,%rdi 3f: e8 .byte 0xe8 and in your case, if we had gone through the loop, then %rax would still contain the return value from page_referenced_one(). But %rax is a kernel pointer, and %r12d is 0. So again, it's actually anon_vma.head.next that is NULL, not any of the entries on the list itself. Now, I can see several cases for this: - the obvious one: anon_vma just wasn't correctly initialized, and is missing a INIT_LIST_HEAD(&anon_vma->head). That's either a slab bug (we don't have a whole lot of coverage of constructors), or somebody allocated an anon_vma without using the anon_vma_cachep. - Related to the above: perhaps the RCU freeing isn't working, or slub/slab/slob ends up reusing the allocations for something else than anonvma's, so together with the race _and_ an unlucky re-use, you get some odd crud. I haven't looked at the kernel config files: do they perhaps share the same (odd?) SLUB/SLAB/SLOB config? - anon_vma isn't actually an anonvma at all. 'page->mapping' was crud with the low bit set. That sounds unlikely, but who knows. The ksm code sets mapping to "stable_node + PAGE_MAPPING_ANON | PAGE_MAPPING_KSM" Did people have KSM enabled? .. and probably other things I haven't even thought about. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists