With kernel version 3.6-rc2 on a Dell Poweredge 2600 I experienced a NULL pointer dereference that did not occur with on 3.5. I believe the error is related to commit de3910eb79a "edac: change the mem allocation scheme to make Documentation/kobject.txt happy" [1] and the fact that my system is going through an error path in the e7xxx_edac driver.
[1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit;h=de3910eb79ac8c0f29a11224661c0ebaaf813039 This is the OOPS: [ 36.703479] BUG: unable to handle kernel NULL pointer dereference at (null) [ 36.703479] IP: [<c045e195>] __wake_up_common+0x1a/0x6a [ 36.703479] *pde = 7f0c6067 [ 36.703479] Oops: 0000 [#1] SMP [ 36.703479] Modules linked in: parport_pc parport floppy e7xxx_edac(+) ide_cd_mod edac_core intel_rng cdrom microcode(+) dm_snapshot dm_zero dm_mirror dm_region_hash d [ 36.703479] Pid: 933, comm: modprobe Tainted: G W 3.6.0-rc2-00111-gc1999ee #12 Dell Computer Corporation PowerEdge 2600 /0F0364 [ 36.703479] EIP: 0060:[<c045e195>] EFLAGS: 00010093 CPU: 3 [ 36.703479] EIP is at __wake_up_common+0x1a/0x6a [ 36.703479] EAX: f47b0984 EBX: fffffff4 ECX: 00000000 EDX: 00000003 [ 36.703479] ESI: f47b0984 EDI: 00000282 EBP: f3dc7d38 ESP: f3dc7d1c [ 36.703479] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 36.703479] CR0: 8005003b CR2: 00000000 CR3: 347d4000 CR4: 000007d0 [ 36.703479] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 36.703479] DR6: ffff0ff0 DR7: 00000400 [ 36.703479] Process modprobe (pid: 933, ti=f3dc6000 task=f3db9520 task.ti=f3dc6000) [ 36.703479] Stack: [ 36.703479] 00000000 00000000 00000003 c046701a f47b0980 f47b0984 00000282 f3dc7d54 [ 36.703479] c046703f 00000000 00000000 f47b08b0 f47b08b0 00000000 f3dc7d74 c06961ce [ 36.703479] f3dc7d74 f3dc7d80 c05e2837 c094c4cc f47b08b0 f47b08b0 f3dc7d88 c068d56d [ 36.703479] Call Trace: [ 36.703479] [<c046701a>] ? complete_all+0x1a/0x50 [ 36.703479] [<c046703f>] complete_all+0x3f/0x50 [ 36.703479] [<c06961ce>] device_pm_remove+0x23/0xa2 [ 36.703479] [<c05e2837>] ? kobject_put+0x5b/0x5d [ 36.703479] [<c068d56d>] device_del+0x34/0x142 [ 36.703479] [<f8547884>] edac_unregister_sysfs+0x3b/0x5c [edac_core] [ 36.703479] [<f8545041>] edac_mc_free+0x29/0x2f [edac_core] [ 36.703479] [<f860163f>] e7xxx_probe1+0x268/0x311 [e7xxx_edac] [ 36.703479] [<c0603d00>] ? __pci_enable_device_flags+0x8f/0xd3 [ 36.703479] [<f8601b0b>] e7xxx_init_one+0x56/0x61 [e7xxx_edac] [ 36.703479] [<c0604f85>] local_pci_probe+0x13/0x15 [ 36.703479] [<c0605115>] pci_call_probe+0x1c/0x1e [ 36.703479] [<c0605158>] __pci_device_probe+0x41/0x4e [ 36.703479] [<c060579c>] pci_device_probe+0x26/0x39 [ 36.703479] [<c06901ed>] really_probe+0x101/0x2a1 [ 36.703479] [<c0690680>] ? __driver_attach+0x3d/0x6e [ 36.703479] [<c0690680>] ? __driver_attach+0x3d/0x6e [ 36.703479] [<c07e0000>] ? quirk_usb_disable_ehci+0xa3/0x141 [ 36.703479] [<c06903c2>] driver_probe_device+0x35/0x79 [ 36.703479] [<c06906af>] __driver_attach+0x6c/0x6e [ 36.703479] [<c068eb25>] bus_for_each_dev+0x44/0x62 [ 36.703479] [<c068ff00>] driver_attach+0x1e/0x20 [ 36.703479] [<c0690643>] ? device_attach+0x98/0x98 [ 36.703479] [<c068fa12>] bus_add_driver+0xc5/0x1c8 [ 36.703479] [<c0605beb>] ? store_new_id+0xfa/0xfa [ 36.703479] [<c0690bfb>] driver_register+0x52/0xd6 [ 36.703479] [<f8604000>] ? 0xf8603fff [ 36.703479] [<c0605a30>] __pci_register_driver+0x4b/0x73 [ 36.703479] [<f8604000>] ? 0xf8603fff [ 36.703479] [<f8604055>] e7xxx_init+0x55/0x57 [e7xxx_edac] [ 36.703479] [<c040120e>] do_one_initcall+0xa3/0xe0 [ 36.703479] [<c0491023>] sys_init_module+0x70/0x1af [ 36.703479] [<c04823a9>] ? trace_hardirqs_on_caller+0x56/0xf9 [ 36.703479] [<c05ec7e8>] ? trace_hardirqs_on_thunk+0xc/0x10 [ 36.703479] [<c07f678c>] sysenter_do_call+0x12/0x32 [ 36.703479] Code: 5d c3 55 89 e5 3e 8d 74 26 00 e8 8f ff ff ff 5d c3 55 89 e5 57 56 53 83 ec 10 3e 8d 74 26 00 89 55 ec 89 4d e8 8b 58 28 83 eb 0c <8b> 53 0c 83 c0 28 [ 36.703479] EIP: [<c045e195>] __wake_up_common+0x1a/0x6a SS:ESP 0068:f3dc7d1c [ 36.703479] CR2: 0000000000000000 [ 36.703479] ---[ end trace 6fcfddc0eef7bbd8 ]--- When I enabled edac debugging I saw the following printed to the kernel log prior to the above BUG: EDAC MC: Ver: 3.0.0 EDAC DEBUG: edac_mc_sysfs_init: device mc created EDAC DEBUG: e7xxx_init_one: EDAC DEBUG: e7xxx_probe1: mci EDAC DEBUG: edac_mc_alloc: errcount layer 0 size 8 EDAC DEBUG: edac_mc_alloc: errcount layer 1 size 16 EDAC DEBUG: edac_mc_alloc: allocating 48 error counters EDAC DEBUG: edac_mc_alloc: allocating 1068 bytes for mci data (16 ranks, 16 csrows/channels) EDAC DEBUG: e7xxx_probe1: init mci EDAC DEBUG: e7xxx_probe1: init pvt EDAC e7xxx: error reporting device not found:vendor 8086 device 0x2541 (broken BIOS?) EDAC DEBUG: edac_mc_free: Floppy drive(s): fd0 is 1.44M EDAC DEBUG: edac_unregister_sysfs: Unregistering device (null) There are probably better ways to accomplish what the following patches are doing but I thought I would send along what I had if only to motivate any discussion. I also have resent Fengguang Wu's patch in this series since I found that it was required as well. Shaun Ruffell (2): edac: Remove invalid kfree in error path of edac_mc_allocate(). edac: edac_mc_free() cannot assume mem_ctl_info is registered in sysfs. drivers/edac/edac_mc.c | 60 +++++++++++++++++++++++++++++--------------------- 1 file changed, 35 insertions(+), 25 deletions(-) -- 1.7.11.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/