4.7-rc2 is very unstable on my Dell laptop, while 4.6 runs fine (with occasional minor errors). During the last testing I saw two error messages before the system hanged, and brcmfmac seems to be cause. I am happy to provide more details if needed. MESSAGE 1: BUG: unable to handle kernel NULL pointer dereference at 0000000000000048 IP: [<ffffffff814c3ed6>] enqueue_to_backlog+0x56/0x260 PGD 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: xt_connmark iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntr i2c_i801 soundcore rtsx_pci_ms brcmutil memstick idma64 cfg80211 mei_me mei intel_lpss_pci processor_th CPU: 1 PID: 433 Comm: irq/137-brcmf_p Tainted: G O 4.7.0-rc2-mainline #1 Hardware name: Dell Inc. XPS 15 9550/0N7TVV, BIOS 01.02.00 04/07/2016 task: ffff8804a13edb80 ti: ffff88049af4c000 task.ti: ffff88049af4c000 RIP: 0010:[<ffffffff814c3ed6>] [<ffffffff814c3ed6>] enqueue_to_backlog+0x56/0x260 RSP: 0018:ffff88049af4fca0 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff8804bdc57c40 RCX: 000000000000007d RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8804bdc57d4c RBP: ffff88049af4fce8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000729 R11: 000000000000094b R12: 0000000000017c40 R13: ffff88049af4fd08 R14: ffff8804a8ad0f00 R15: ffff8804bdc57d4c FS: 0000000000000000(0000) GS:ffff8804bdc40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000048 CR3: 0000000001806000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff88049af4fcb0 ffffffff814b34f1 ffff88049af4fcd8 0000000000000282 0000000000000000 ffff8804a8ad0f00 ffff8804a8e86800 ffff8804a8ad0f00 ffff880036c34000 ffff88049af4fd28 ffffffff814c412b ffffffff813120d3 Call Trace: [<ffffffff814b34f1>] ? skb_free_head+0x21/0x30 [<ffffffff814c412b>] netif_rx_internal+0x4b/0x170 [<ffffffff813120d3>] ? swiotlb_tbl_unmap_single+0xf3/0x120 [<ffffffff814c5657>] netif_rx_ni+0x27/0xc0 [<ffffffffa071d9e9>] brcmf_netif_rx+0x49/0x70 [brcmfmac] [<ffffffffa07224d4>] brcmf_msgbuf_process_rx+0x2b4/0x570 [brcmfmac] [<ffffffff81020071>] ? __xen_set_pgd_hyper+0xb1/0xd0 [<ffffffff810d60b0>] ? irq_forced_thread_fn+0x70/0x70 [<ffffffffa0723381>] brcmf_proto_msgbuf_rx_trigger+0x31/0xe0 [brcmfmac] [<ffffffffa072de8f>] brcmf_pcie_isr_thread+0x7f/0x110 [brcmfmac] [<ffffffff810d60d0>] irq_thread_fn+0x20/0x50 [<ffffffff810d63ad>] irq_thread+0x12d/0x1c0 [<ffffffff815d0a65>] ? __schedule+0x2f5/0x7a0 [<ffffffff810d61d0>] ? wake_threads_waitq+0x30/0x30 [<ffffffff810d6280>] ? irq_thread_dtor+0xb0/0xb0 [<ffffffff81098ea8>] kthread+0xd8/0xf0 [<ffffffff815d4e3f>] ret_from_fork+0x1f/0x40 [<ffffffff81098dd0>] ? kthread_worker_fn+0x170/0x170 Code: 1c f5 60 9a 8e 81 9c 58 0f 1f 44 00 00 48 89 45 d0 fa 66 0f 1f 44 00 00 4c 8d bb 0c 01 00 00 4c 89 RIP [<ffffffff814c3ed6>] enqueue_to_backlog+0x56/0x260 RSP <ffff88049af4fca0> CR2: 0000000000000048 ---[ end trace bf3ebb7302f9750e ]--- note: irq/137-brcmf_p[433] exited with preempt_count 3 BUG: unable to handle kernel paging request at ffffffffffffffd8 IP: [<ffffffff810993f0>] kthread_data+0x10/0x20 PGD 1809067 PUD 180b067 PMD 0 Oops: 0000 [#2] PREEMPT SMP MESSAGE 2: Modules linked in: xt_connmark iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntr i2c_i801 soundcore rtsx_pci_ms brcmutil memstick idma64 cfg80211 mei_me mei intel_lpss_pci processor_th CPU: 1 PID: 433 Comm: irq/137-brcmf_p Tainted: G D O 4.7.0-rc2-mainline #1 Hardware name: Dell Inc. XPS 15 9550/0N7TVV, BIOS 01.02.00 04/07/2016 task: ffff8804a13edb80 ti: ffff88049af4c000 task.ti: ffff88049af4c000 RIP: 0010:[<ffffffff810993f0>] [<ffffffff810993f0>] kthread_data+0x10/0x20 RSP: 0018:ffff88049af4f9a0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8804a13edb80 RCX: 0000000000000000 RDX: ffff88049af4fe80 RSI: 0000000000000000 RDI: ffff8804a13edb80 RBP: ffff88049af4f9a0 R08: 0000000000000000 R09: 0000000000000005 R10: 00000000ffffffff R11: ffffffff81a7ab4d R12: 0000000000000000 R13: ffff8804a13ee268 R14: 0000000000000000 R15: ffff8804a13edb80 FS: 0000000000000000(0000) GS:ffff8804bdc40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd8 CR3: 0000000001806000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff88049af4f9c0 ffffffff810d61f3 ffffffff81a76650 0000000000000000 ffff88049af4f9f8 ffffffff81097114 ffff8804a13edb80 ffff88049af4fa28 0000000000000000 0000000000000048 0000000000000046 ffff88049af4fa68 Call Trace: [<ffffffff810d61f3>] irq_thread_dtor+0x23/0xb0 [<ffffffff81097114>] task_work_run+0x84/0xa0 [<ffffffff8107dbf8>] do_exit+0x3b8/0xb60 [<ffffffff8103175c>] oops_end+0x9c/0xd0 [<ffffffff81065ca6>] no_context+0x176/0x3a0 [<ffffffff81065fe3>] __bad_area_nosemaphore+0x113/0x210 [<ffffffff810b0cbd>] ? enqueue_entity+0x1fd/0xdb0 [<ffffffff810aa3cc>] ? __enqueue_entity+0x6c/0x70 [<ffffffff810660f4>] bad_area_nosemaphore+0x14/0x20 [<ffffffff810664c4>] __do_page_fault+0xd4/0x510 [<ffffffff810b1913>] ? enqueue_task_fair+0xa3/0x940 [<ffffffff81066922>] do_page_fault+0x22/0x30 [<ffffffff815d6c38>] page_fault+0x28/0x30 [<ffffffff814c3ed6>] ? enqueue_to_backlog+0x56/0x260 [<ffffffff814b34f1>] ? skb_free_head+0x21/0x30 [<ffffffff814c412b>] netif_rx_internal+0x4b/0x170 [<ffffffff813120d3>] ? swiotlb_tbl_unmap_single+0xf3/0x120 [<ffffffff814c5657>] netif_rx_ni+0x27/0xc0 [<ffffffffa071d9e9>] brcmf_netif_rx+0x49/0x70 [brcmfmac] [<ffffffffa07224d4>] brcmf_msgbuf_process_rx+0x2b4/0x570 [brcmfmac] [<ffffffff81020071>] ? __xen_set_pgd_hyper+0xb1/0xd0 [<ffffffff810d60b0>] ? irq_forced_thread_fn+0x70/0x70 [<ffffffffa0723381>] brcmf_proto_msgbuf_rx_trigger+0x31/0xe0 [brcmfmac] [<ffffffffa072de8f>] brcmf_pcie_isr_thread+0x7f/0x110 [brcmfmac] [<ffffffff810d60d0>] irq_thread_fn+0x20/0x50 [<ffffffff810d63ad>] irq_thread+0x12d/0x1c0 [<ffffffff815d0a65>] ? __schedule+0x2f5/0x7a0 [<ffffffff810d61d0>] ? wake_threads_waitq+0x30/0x30 [<ffffffff810d6280>] ? irq_thread_dtor+0xb0/0xb0 [<ffffffff81098ea8>] kthread+0xd8/0xf0 [<ffffffff815d4e3f>] ret_from_fork+0x1f/0x40 [<ffffffff81098dd0>] ? kthread_worker_fn+0x170/0x170 Code: 5c 5d c3 e8 4b 9c f6 ff e9 e2 fe ff ff 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 RIP [<ffffffff810993f0>] kthread_data+0x10/0x20 RSP <ffff88049af4f9a0> CR2: ffffffffffffffd8 ---[ end trace bf3ebb7302f9750f ]--- Fixing recursive fault but reboot is needed! Here's the output of lspci -v: 02:00.0 Network controller: Broadcom Corporation BCM43602 802.11ac Wireless LAN SoC (rev 01) Subsystem: Dell Device 0024 Flags: bus master, fast devsel, latency 0, IRQ 137 Memory at dd800000 (64-bit, non-prefetchable) [size=32K] Memory at dd400000 (64-bit, non-prefetchable) [size=4M] Capabilities: [48] Power Management version 3 Capabilities: [58] MSI: Enable+ Count=1/16 Maskable- 64bit+ Capabilities: [68] Vendor Specific Information: Len=44 <?> Capabilities: [ac] Express Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting Capabilities: [13c] Device Serial Number dc-23-a8-ff-ff-e1-44-1c Capabilities: [150] Power Budgeting <?> Capabilities: [160] Virtual Channel Capabilities: [1b0] Latency Tolerance Reporting Capabilities: [220] #15 Capabilities: [240] L1 PM Substates Kernel driver in use: brcmfmac Kernel modules: brcmfmac
This report might be dupe of Bug 119451, which should be fixed as of https://git.kernel.org/torvalds/c/31143e2933d1675c4c1ba6ce125cdd95870edd85 (merged two days ago). Please check and if the bug still shows up in rc3 (due later today); if not please consider reproducing the problem without loading external drivers (the tainted flag indicates a out-of-tree module was loaded).
Sorry I did not have time to test it until now. I am running 4.7 rc4 and it looks stable on my machine except some screen flickering. (There are other tickets for the flickering problem.) I think this bug was fixed as you described, and please feel free to mark it as resolved.
(In reply to favonia from comment #2) > I think this bug was fixed as you described, thx for the feedback. > and please feel free to mark it as resolved. I'm currently lacking permissions to do so, can you do that yourself please? tia!
Possibly a duplicate of Bug 119451. *** This bug has been marked as a duplicate of bug 119451 ***