Srivatsa S. Bhat b11e3d782b x86, mce: Fix rcu splat in drain_mce_log_buffer() ... While booting, the following message is seen: [ 21.665087] =============================== [ 21.669439] [ INFO: suspicious RCU usage. ] [ 21.673798] 3.2.0-0.0.0.28.36b5ec9-default #2 Not tainted [ 21.681353] ------------------------------- [ 21.685864] arch/x86/kernel/cpu/mcheck/mce.c:194 suspicious rcu_dereference_index_check() usage! [ 21.695013] [ 21.695014] other info that might help us debug this: [ 21.695016] [ 21.703488] [ 21.703489] rcu_scheduler_active = 1, debug_locks = 1 [ 21.710426] 3 locks held by modprobe/2139: [ 21.714754] #0: (&__lockdep_no_validate__){......}, at: [<ffffffff8133afd3>] __driver_attach+0x53/0xa0 [ 21.725020] #1: [ 21.725323] ioatdma: Intel(R) QuickData Technology Driver 4.00 [ 21.733206] (&__lockdep_no_validate__){......}, at: [<ffffffff8133afe1>] __driver_attach+0x61/0xa0 [ 21.743015] #2: (i7core_edac_lock){+.+.+.}, at: [<ffffffffa01cfa5f>] i7core_probe+0x1f/0x5c0 [i7core_edac] [ 21.753708] [ 21.753709] stack backtrace: [ 21.758429] Pid: 2139, comm: modprobe Not tainted 3.2.0-0.0.0.28.36b5ec9-default #2 [ 21.768253] Call Trace: [ 21.770838] [<ffffffff810977cd>] lockdep_rcu_suspicious+0xcd/0x100 [ 21.777366] [<ffffffff8101aa41>] drain_mcelog_buffer+0x191/0x1b0 [ 21.783715] [<ffffffff8101aa78>] mce_register_decode_chain+0x18/0x20 [ 21.790430] [<ffffffffa01cf8db>] i7core_register_mci+0x2fb/0x3e4 [i7core_edac] [ 21.798003] [<ffffffffa01cfb14>] i7core_probe+0xd4/0x5c0 [i7core_edac] [ 21.804809] [<ffffffff8129566b>] local_pci_probe+0x5b/0xe0 [ 21.810631] [<ffffffff812957c9>] __pci_device_probe+0xd9/0xe0 [ 21.816650] [<ffffffff813362e4>] ? get_device+0x14/0x20 [ 21.822178] [<ffffffff81296916>] pci_device_probe+0x36/0x60 [ 21.828061] [<ffffffff8133ac8a>] really_probe+0x7a/0x2b0 [ 21.833676] [<ffffffff8133af23>] driver_probe_device+0x63/0xc0 [ 21.839868] [<ffffffff8133b01b>] __driver_attach+0x9b/0xa0 [ 21.845718] [<ffffffff8133af80>] ? driver_probe_device+0xc0/0xc0 [ 21.852027] [<ffffffff81339168>] bus_for_each_dev+0x68/0x90 [ 21.857876] [<ffffffff8133aa3c>] driver_attach+0x1c/0x20 [ 21.863462] [<ffffffff8133a64d>] bus_add_driver+0x16d/0x2b0 [ 21.869377] [<ffffffff8133b6dc>] driver_register+0x7c/0x160 [ 21.875220] [<ffffffff81296bda>] __pci_register_driver+0x6a/0xf0 [ 21.881494] [<ffffffffa01fe000>] ? 0xffffffffa01fdfff [ 21.886846] [<ffffffffa01fe047>] i7core_init+0x47/0x1000 [i7core_edac] [ 21.893737] [<ffffffff810001ce>] do_one_initcall+0x3e/0x180 [ 21.899670] [<ffffffff810a9b95>] sys_init_module+0xc5/0x220 [ 21.905542] [<ffffffff8149bc39>] system_call_fastpath+0x16/0x1b Fix this by using ACCESS_ONCE() instead of rcu_dereference_check_mce() over mcelog.next. Since the access to each entry is controlled by the ->finished field, ACCESS_ONCE() should work just fine. An rcu_dereference is unnecessary here. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>		2012-03-07 11:44:29 +01:00
..
boot	x86/boot-image: Don't leak phdrs in arch/x86/boot/compressed/misc.c::Parse_elf()	2012-01-26 11:30:29 +01:00
configs	iommu: Rename the DMAR and INTR_REMAP config options	2011-09-21 10:22:03 +02:00
crypto	crypto: serpent-sse2 - remove unneeded LRW/XTS #ifdefs	2011-12-20 15:20:08 +08:00
ia32	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit	2012-01-17 16:41:31 -08:00
include/asm	perf/x86/kvm: Fix Host-Only/Guest-Only counting with SVM disabled	2012-03-02 12:16:39 +01:00
kernel	x86, mce: Fix rcu splat in drain_mce_log_buffer()	2012-03-07 11:44:29 +01:00
kvm	perf/x86/kvm: Fix Host-Only/Guest-Only counting with SVM disabled	2012-03-02 12:16:39 +01:00
lguest	lguest: Make sure interrupt is allocated ok by lguest_setup_irq	2012-01-12 15:44:47 +10:30
lib	Merge branches 'sched-urgent-for-linus', 'perf-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2012-01-19 14:53:06 -08:00
math-emu
mm	Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', 'sched-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2012-02-02 11:11:13 -08:00
net	net: bpf_jit: fix divide by 0 generation	2012-01-18 16:04:26 -05:00
oprofile	Merge branch 'core' of git://amd64.org/linux/rric into perf/core	2011-11-15 11:05:18 +01:00
pci	xen pvhvm: do not remap pirqs onto evtchns if !xen_have_vector_callback	2012-02-03 16:06:27 -05:00
platform	x86/uv: Fix uninitialized spinlocks	2012-01-26 10:58:34 +01:00
power	x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE	2011-10-31 19:30:35 -04:00
syscalls	x86, syscall: Allow syscall offset to be symbolic	2011-11-18 17:01:19 -08:00
tools	x86/tools: Add decoded instruction dump mode	2011-12-05 14:53:23 +01:00
um	uml: fix compile for x86-64	2012-01-18 19:26:11 -08:00
vdso	Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2011-10-28 05:03:12 -07:00
video	x86: fix up files really needing to include module.h	2011-10-31 19:30:36 -04:00
xen	xen/pat: Disable PAT support for now.	2012-02-20 10:41:35 -05:00
.gitignore	x86/kprobes: Add arch/x86/tools/insn_sanity to .gitignore	2012-01-16 08:21:59 +01:00
Kbuild
Kconfig	x86/numachip: Drop unnecessary conflict with EDAC	2012-01-26 11:03:03 +01:00
Kconfig.cpu	mm,x86,um: move CMPXCHG_DOUBLE config option	2012-01-12 20:13:03 -08:00
Kconfig.debug	Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2012-01-11 19:13:40 -08:00
Makefile	x86: Generate system call tables and unistd_*.h from tables	2011-11-17 13:35:37 -08:00
Makefile.um	um: take arch/um/sys-x86 to arch/x86/um	2011-11-02 14:15:05 +01:00
Makefile_32.cpu