Messages in this thread | | | From | Vegard Nossum <> | Subject | slub freelist issue / BUG: unable to handle page fault for address: 000000003ffe0018 | Date | Thu, 4 Jun 2020 19:14:35 +0200 |
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Hi all,
I ran into a boot problem with latest linus/master (6929f71e46bdddbf1c4d67c2728648176c67c555) that manifests like this:
hpet0: 3 comparators, 64-bit 100.000000 MHz counter clocksource: Switched to clocksource tsc-early BUG: unable to handle page fault for address: 000000003ffe0018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0+ #211 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 RIP: 0010:kmem_cache_alloc+0x70/0x1d0 Code: 00 00 4c 8b 45 00 65 49 8b 50 08 65 4c 03 05 6f cc e7 7e 4d 8b 20 4d 85 e4 0f 84 3d 01 00 00 8b 45 20 48 8b 7d 00 48 8d 4a 01 <49> 8b 1c 04 4c 89 e0 65 48 0f c7 0f 0f 94 c0 84 c0 74 c5 8b 45 20 RSP: 0000:ffffc90000013df8 EFLAGS: 00010206 RAX: 0000000000000018 RBX: ffffffff81c49200 RCX: 0000000000000002 RDX: 0000000000000001 RSI: 0000000000000dc0 RDI: 000000000002b300 RBP: ffff88803e403d00 R08: ffff88803ec2b300 R09: 0000000000000001 R10: 0000000000000dc0 R11: 0000000000000006 R12: 000000003ffe0000 R13: ffffffff8110a583 R14: 0000000000000dc0 R15: ffffffff81c49a80 FS: 0000000000000000(0000) GS:ffff88803ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000003ffe0018 CR3: 0000000001c0a001 CR4: 00000000003606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __trace_define_field+0x33/0xa0 event_trace_init+0xeb/0x2b4 tracer_init_tracefs+0x60/0x195 ? register_tracer+0x1e7/0x1e7 do_one_initcall+0x74/0x160 kernel_init_freeable+0x190/0x1f0 ? rest_init+0x9a/0x9a kernel_init+0x5/0xf6 ret_from_fork+0x35/0x40 CR2: 000000003ffe0018 ---[ end trace 707efa023f2ee960 ]--- RIP: 0010:kmem_cache_alloc+0x70/0x1d0
Bisection gives me:
commit 3202fa62fb43087387c65bfa9c100feffac74aa6 Author: Kees Cook <keescook@chromium.org> Date: Wed Apr 1 21:04:27 2020 -0700
slub: relocate freelist pointer to middle of object
Reverting these three commits fixes it:
3202fa62fb43087387c65bfa9c100feffac74aa6 slub: relocate freelist pointer to middle of object 89b83f282d8ba380cf2124f88106c57df49c538c slub: avoid redzone when choosing freepointer location cbfc35a48609ceac978791e3ab9dde0c01f8cb20 mm/slub: fix incorrect interpretation of s->offset
Vegard
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