Messages in this thread Patch in this message | | | Date | Wed, 17 Jul 2019 10:07:25 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 0/6] Tracing vs CR2 |
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On Tue, Jul 16, 2019 at 09:33:50PM +0200, Vegard Nossum wrote: > ------------[ cut here ]------------ > General protection fault in user access. Non-canonical address? > WARNING: CPU: 0 PID: 5039 at arch/x86/mm/extable.c:126 > ex_handler_uaccess+0x5d/0x70 > CPU: 0 PID: 5039 Comm: init Not tainted 5.2.0+ #124 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > Ubuntu-1.8.2-1ubuntu1 04/01/2014 > RIP: 0010:ex_handler_uaccess+0x5d/0x70 > Code: 5d 41 5c c3 e8 c4 8e 0e 00 80 3d e5 74 1e 01 00 75 d3 e8 b6 8e 0e 00 > 48 c7 c7 10 a7 fb 81 c6 05 d0 74 1e 01 01 e8 d1 43 01 00 <0f> 0b eb b7 0f 1f > 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 > RSP: 0000:fffffe000000fc48 EFLAGS: 00010086 > RAX: 0000000000000000 RBX: ffffffff81c07dac RCX: ffffffff811a887c > RDX: 0000000000000000 RSI: ffffffff8289f05f RDI: 0000000000000093 > RBP: fffffe000000fcb8 R08: 00000036fe0f15d3 R09: 000000000000003f > R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000d > R13: 000000000000000d R14: 0000000000000000 R15: 0000000000000000 > FS: 00005555563ab8c0(0000) GS:ffff88803ec00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000001ff7 CR3: 000000003c804002 CR4: 00000000003606f0 > DR0: 0000000040209100 DR1: 00000000402091a1 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 00000000000b062a > Call Trace: > <#DB> > fixup_exception+0x50/0x6a > do_general_protection+0x40/0x160 > general_protection+0x2d/0x40 > RIP: 0010:arch_stack_walk_user+0x71/0x100 > Code: 00 48 83 e8 10 49 39 c4 77 45 4c 8b 04 24 4c 89 e3 4d 89 fd 4c 89 fd > 41 83 87 98 0a 00 00 01 0f 01 cb 0f ae e8 31 c0 4c 89 e2 <4c> 8b 33 4d 89 f4 > 85 c0 75 7a 48 8b 73 08 0f 01 ca 85 c0 74 1f 65 > RSP: 0000:fffffe000000fd68 EFLAGS: 00050046 > RAX: 0000000000000000 RBX: 854163717acc2789 RCX: ffffffff811ca27b > RDX: 854163717acc2789 RSI: 0000000040209102 RDI: fffffe000000fdb8 > RBP: ffff88803d55d040 R08: ffffc9000520bf58 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 854163717acc2789 > R13: ffff88803d55d040 R14: 0000000000000093 R15: ffff88803d55d040 > ? stack_trace_consume_entry+0x4b/0x80 > ? arch_stack_walk_user+0x34/0x100 > ? profile_setup.cold+0xc1/0xc1 > stack_trace_save_user+0x71/0x9c > trace_buffer_unlock_commit_regs+0x1ae/0x270 > trace_event_buffer_commit+0x90/0x240 > trace_event_raw_event_preemptirq_template+0x9a/0x100 > ? debug+0x16/0x70 > ? perf_trace_preemptirq_template+0x120/0x120 > ? trace_hardirqs_off_thunk+0x1a/0x1c > trace_hardirqs_off_caller+0xf4/0x150 > trace_hardirqs_off_thunk+0x1a/0x1c > ? debug+0x11/0x70 > debug+0x16/0x70 > RIP: 0010:copy_user_generic_unrolled+0xa0/0xc0 > Code: 7f 40 ff c9 75 b6 89 d1 83 e2 07 c1 e9 03 74 12 4c 8b 06 4c 89 07 48 > 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10 89 d1 8a 06 <88> 07 48 ff c6 48 > ff c7 ff c9 75 f2 31 c0 0f 01 ca c3 0f 1f 40 00 > RSP: 0000:ffffc9000520be38 EFLAGS: 00040202 > RAX: ffff88803d55d09c RBX: ffff88803d55d040 RCX: 0000000000000001 > RDX: 0000000000000001 RSI: 0000000040209102 RDI: ffffc9000520be76 > RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 00007ffffffff000 > R13: 0000000040209102 R14: ffffc9000520be76 R15: 0000000000000000 > </#DB> > __probe_kernel_read+0x57/0x90 > is_prefetch.isra.0+0xb5/0x210 > ? tracer_hardirqs_on+0x53/0x1a0 > __bad_area_nosemaphore+0x9e/0x220 > __do_page_fault+0x483/0x630 > ? async_page_fault+0x8/0x40 > async_page_fault+0x36/0x40 > RIP: 0033:0x40209102 > Code: 00 00 49 bc 00 20 23 40 00 00 00 00 49 bd 00 00 d0 40 00 00 00 00 49 > be ff ff ff ff ff ff ff ff 49 bf 00 50 80 40 00 00 00 00 <9c> 48 81 0c 24 00 > 04 00 00 48 81 0c 24 00 00 04 00 9d ff 2c 25 00 > RSP: 002b:0000000000001fff EFLAGS: 00010217 > RAX: 0000000000000000 RBX: 00000000402090b0 RCX: 0000000000000001 > RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000041ebb000 > RBP: 854163717acc2789 R08: 0000000000000001 R09: b1f39cc399a61ebb > R10: 00007ffeab175000 R11: 0000000000000360 R12: 0000000040232000 > R13: 0000000040d00000 R14: ffffffffffffffff R15: 0000000040805000 > ---[ end trace e5e49800ff5aa5ed ]---
https://lkml.kernel.org/r/57754f11-2c65-a2c8-2f6d-bfab0d2f8b53@etsukata.com
Does something like the below help?
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index c8d0f05721a1..80ad4ccb7025 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -226,12 +226,16 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) .store = store, .size = size, }; + mm_segment_t fs; /* Trace user stack if not a kernel thread */ if (current->flags & PF_KTHREAD) return 0; + fs = get_fs(); + set_fs(USER_DS); arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); + set_fs(fs); return c.len; } #endif
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