On Fri, Mar 16, 2018 at 12:48:49PM +0100, Borislav Petkov wrote: > [ 29.046500] sysrq: SysRq : Trigger a crash > [ 29.048605] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000000 > [ 29.051639] PGD 79afd067 P4D 79afd067 PUD 7a1a2067 PMD 0 > [ 29.052557] Oops: 0002 [#1] PREEMPT SMP > [ 29.052557] CPU: 7 PID: 3693 Comm: bash Not tainted 4.16.0-rc5+ #8 > [ 29.052557] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > 1.10.2-1 04/01/2014 > [ 29.052557] RIP: 0010:sysrq_handle_crash+0x17/0x20 > [ 29.052557] Code: d1 e8 6d 08 b7 ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 > 0f 1f 44 00 00 e8 76 1f bd ff c7 05 a4 12 19 01 01 00 00 00 0f ae f8 <c6> 04 > 25 00 00 00 00 01 c3 0f 1f 44 00 00 e8 c6 1b c2 ff fb e9 80 > [ 29.052557] RSP: 0018:ffffc900007cbdf0 EFLAGS: 00010246 > [ 29.052557] RAX: 0000000000000000 RBX: 0000000000000063 RCX: > 0000000000000000 > [ 29.052557] RDX: 0000000000000000 RSI: ffffffff81101e0a RDI: > 0000000000000063 > [ 29.052557] RBP: ffffffff822714c0 R08: 0000000000000185 R09: > 000000000000b5a4 > [ 29.052557] R10: 0000000000000000 R11: 0000000000000000 R12: > 000000000000000a > [ 29.052557] R13: 0000000000000000 R14: 0000000000000000 R15: > 0000000000000000 > [ 29.052557] FS: 00007ffff7fdb700(0000) GS:ffff88007edc0000(0000) > knlGS:0000000000000000 > [ 29.052557] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 29.052557] CR2: 0000000000000000 CR3: 00000000799e1000 CR4: > 00000000000406e0 > [ 29.052557] Call Trace: > [ 29.052557] __handle_sysrq+0x9e/0x160 > [ 29.052557] write_sysrq_trigger+0x2b/0x30 > [ 29.052557] proc_reg_write+0x38/0x70 > [ 29.052557] __vfs_write+0x36/0x160 > [ 29.052557] ? __fd_install+0x69/0x110 > [ 29.052557] ? preempt_count_add+0x74/0xb0 > [ 29.052557] ? _raw_spin_lock+0x13/0x30 > [ 29.052557] ? set_close_on_exec+0x41/0x80 > [ 29.052557] ? preempt_count_sub+0xa8/0x100 > [ 29.052557] vfs_write+0xc0/0x190 > [ 29.052557] SyS_write+0x64/0xe0 > [ 29.052557] ? trace_hardirqs_off_thunk+0x1a/0x1c > [ 29.052557] do_syscall_64+0x70/0x130 > [ 29.052557] entry_SYSCALL_64_after_hwframe+0x42/0xb7 > [ 29.052557] RIP: 0033:0x7ffff74b9620 > [ 29.052557] Code: Bad RIP value. > [ 29.052557] RSP: 002b:00007fffffffe6f8 EFLAGS: 00000246 ORIG_RAX: > 0000000000000001 > [ 29.052557] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: > 00007ffff74b9620 > [ 29.052557] RDX: 0000000000000002 RSI: 0000000000705408 RDI: > 0000000000000001 > [ 29.052557] RBP: 0000000000705408 R08: 000000000000000a R09: > 00007ffff7fdb700 > [ 29.052557] R10: 00007ffff77826a0 R11: 0000000000000246 R12: > 00007ffff77842a0 > [ 29.052557] R13: 0000000000000002 R14: 0000000000000001 R15: > 0000000000000000
Hm, the "Code: Bad RIP value" will always be shown for syscall regs, which will probably cause some unnecessary confusion/worry. Should we just skip printing it for the "regs->ip < PAGE_OFFSET" case? -- Josh
