Hi all, I have 3.18.13-rt10 running on a x86 PC (32bit) system. Linux Distribution: Debian 8.1 "Jessie". Fairly often (but not reproducible for me) I got the following kernel bug. I looks like the systemd-journald reads some kind of /proc/PID/status file. BUG: unable to handle kernel NULL pointer dereference at 0000001c IP: [<c107fb62>] __try_to_take_rt_mutex+0x52/0x100 *pde = 00000000 Oops: 0000 [#1] PREEMPT SMP Modules linked in: rtpc_dma(O) es53xx(O) nfsd nfs lockd grace sunrpc bridge stp llc e100 mii e1000 e1000e igb i2c_algo_bit ixgbe mdio ptp pps_core dca kvm_intel kvm ecikm(O) i2c_i801 pcspkr i2c_core video backlight processor coretemp autofs4 reiserfs microcode sg sd_mod ahci libahci ehci_pci ehci_hcd xhci_pci xhci_hcd fan thermal_sys hwmon CPU: 0 PID: 1522 Comm: systemd-journal Tainted: G O 3.18.13-rt10-2 #2 Hardware name: Supermicro X9SAE/X9SAE, BIOS 2.0b 07/10/2013 task: dff76000 ti: f4760000 task.ti: f4760000 EIP: 0060:[<c107fb62>] EFLAGS: 00010282 CPU: 0 EIP is at __try_to_take_rt_mutex+0x52/0x100 EAX: 00000000 EBX: 00000000 ECX: f4761df4 EDX: 00000000 ESI: dff76000 EDI: dfdec944 EBP: f4761dd4 ESP: f4761dc4 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 CR0: 80050033 CR2: f8b5cbc0 CR3: 344ad000 CR4: 001407d0 Stack: dff76000 dfdec944 dff764b0 f4761df4 f4761e28 c1404169 00000001 f4761fec f3ba9201 dff76000 dff764b0 dff76000 00000001 00000000 00000000 f4761e00 00000000 00000000 dff76000 dfdec944 c1045b01 00000078 dff76000 f3bae000 Call Trace: [<c1404169>] rt_spin_lock_slowlock+0xf9/0x240 [<c1045b01>] ? pin_current_cpu+0x31/0x1a0 [<c1405567>] rt_spin_lock+0x27/0x30 [<c1051508>] __lock_task_sighand+0x38/0x70 [<c119768b>] proc_pid_status+0x33b/0x620 [<c1193312>] proc_single_show+0x42/0x80 [<c1163d12>] seq_read+0x82/0x380 [<c11283fa>] ? do_mmap_pgoff+0x27a/0x350 [<c1080abd>] ? rt_up_write+0xd/0x10 [<c1163c90>] ? seq_lseek+0x1c0/0x1c0 [<c1142684>] vfs_read+0x74/0x140 [<c1142ca6>] SyS_read+0x46/0x90 [<c1405c54>] sysenter_do_call+0x12/0x12 Code: 83 cb 01 f0 0f b1 1e 39 d0 75 ee 8b 5f 0c 31 c0 83 e3 fe 74 0c 83 c4 04 5b 5e 5f 5d c3 8d 74 26 00 8b 75 f0 85 c9 74 1d 8b 57 08 <3b> 7a 1c 0f 85 93 00 00 00 89 d8 39 d1 75 db 89 ca 89 f8 e8 c6 EIP: [<c107fb62>] __try_to_take_rt_mutex+0x52/0x100 SS:ESP 0068:f4761dc4 CR2: 000000000000001c ---[ end trace 0000000000 Thanks for any support or proposals on this issue. Mathias -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
