I've been sitting on this for a while and should have spent time to investigate sooner, but it's been an odd failure mode that wasn't quite obvious. In 4.9 if I cold power on my laptop (Dell E7240) it fails to boot - I don't see anything after grub says its booting. In 4.10 onwards the laptop boots, but I get an Oops as part of the boot and ACPI is unhappy (no suspend, no clean poweroff, no ACPI buttons). The Oops is below; taken from 4.12 as that's the most recent error dmesg I have saved but also seen back in 4.10. It's always address 0x30 for the dereference. Rebooting the laptop does not lead to these problems; it's *only* from a complete cold boot that they arise (which didn't help me in terms of being able to reliably bisect). Once I realised that I was able to bisect, but it leads me to an odd commit: 86d9f48534e800e4d62cdc1b5aaf539f4c1d47d6 (mm/slab: fix kmemcg cache creation delayed issue) If I revert this then I can cold boot without problems. Also I don't see the problem with a stock Debian kernel, I think because the ACPI support is modularised. Config, dmesg + bisect log at: https://the.earth.li/~noodles/acpi-problem/ ------- BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 IP: netlink_broadcast_filtered+0x1d/0x3e0 PGD 0 P4D 0 Oops: 0000 [#1] SMP Modules linked in: CPU: 0 PID: 41 Comm: kworker/0:1 Not tainted 4.12.0 #1 Hardware name: Dell Inc. Latitude E7240/07RPNV, BIOS A21 05/08/2017 Workqueue: kacpi_notify acpi_os_execute_deferred task: ffff914e4c321240 task.stack: ffffa3bd4017c000 RIP: 0010:netlink_broadcast_filtered+0x1d/0x3e0 RSP: 0000:ffffa3bd4017fd90 EFLAGS: 00010286 RAX: 0000000000000001 RBX: ffff914e4c82b300 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000001080020 RDI: ffff914e4c82b300 RBP: ffff914e4c305614 R08: 0000000001080020 R09: 0000000000000000 R10: 0000000000000014 R11: ffffffffb8a31d40 R12: 0000000000000000 R13: 0000000000000000 R14: ffff914e4c305614 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff914e5ea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000030 CR3: 0000000236c09000 CR4: 00000000001406f0 Call Trace: ? __kmalloc_reserve.isra.37+0x24/0x70 ? __nlmsg_put+0x63/0x80 ? netlink_broadcast+0xa/0x10 ? acpi_bus_generate_netlink_event+0x10d/0x150 ? acpi_ev_notify_dispatch+0x37/0x4c ? acpi_os_execute_deferred+0xb/0x20 ? process_one_work+0x1cf/0x3c0 ? worker_thread+0x42/0x3c0 ? __schedule+0x26c/0x660 ? kthread+0xf7/0x130 ? create_worker+0x190/0x190 ? kthread_create_on_node+0x40/0x40 ? ret_from_fork+0x22/0x30 Code: c8 c3 66 90 66 2e 0f 1f 84 00 00 00 00 00 41 57 41 89 cf 41 56 41 55 49 89 fd 48 89 f7 44 89 c6 41 54 41 89 d4 55 53 48 83 ec 38 <49> 8b 6d 30 44 89 44 24 24 4c 89 4c 24 28 e8 a0 ec ff ff 48 c7 RIP: netlink_broadcast_filtered+0x1d/0x3e0 RSP: ffffa3bd4017fd90 CR2: 0000000000000030 ---[ end trace f8e25281792d4743 ]--- J. -- /-\ | 101 things you can't have too much |@/ Debian GNU/Linux Developer | of : 47 - More coffee. \- | -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
