[PATCH 3.19 159/175] EDAC, amd64_edac: Prevent OOPS with >16 memory controllers

Greg Kroah-Hartman
2015-03-04T06:29:39Z

From: Daniel J Blueman <daniel@numascale.com>

commit 0c510cc83bdbaac8406f4f7caef34f4da0ba35ea upstream.

When DRAM errors occur on memory controllers after EDAC_MAX_MCS (16),
the kernel fatally dereferences unallocated structures, see splat below;
this occurs on at least NumaConnect systems.

Fix by checking if a memory controller info structure was found.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000320
IP: [<ffffffff819f714f>] decode_bus_error+0x2f/0x2b0
PGD 2f8b5a3067 PUD 2f8b5a2067 PMD 0
Oops: 0000 [#2] SMP
Modules linked in:
CPU: 224 PID: 11930 Comm: stream_c.exe.gn Tainted: G D 3.19.0 #1
Hardware name: Supermicro H8QGL/H8QGL, BIOS 3.5b 01/28/2015
task: ffff8807dbfb8c00 ti: ffff8807dd16c000 task.ti: ffff8807dd16c000
RIP: 0010:[<ffffffff819f714f>] [<ffffffff819f714f>] decode_bus_error+0x2f/0x2b0
RSP: 0000:ffff8907dfc03c48 EFLAGS: 00010297
RAX: 0000000000000001 RBX: 9c67400010080a13 RCX: 0000000000001dc6
RDX: 000000001dc61dc6 RSI: ffff8907dfc03df0 RDI: 000000000000001c
RBP: ffff8907dfc03ce8 R08: 0000000000000000 R09: 0000000000000022
R10: ffff891fffa30380 R11: 00000000001cfc90 R12: 0000000000000008
R13: 0000000000000000 R14: 000000000000001c R15: 00009c6740001000
FS: 00007fa97ee18700(0000) GS:ffff8907dfc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000320 CR3: 0000003f889b8000 CR4: 00000000000407e0
Stack:
0000000000000000 ffff8907dfc03df0 0000000000000008 9c67400010080a13
000000000000001c 00009c6740001000 ffff8907dfc03c88 ffffffff810e4f9a
ffff8907dfc03ce8 ffffffff81b375b9 0000000000000000 0000000000000010
Call Trace:
<IRQ>
? vprintk_default
? printk
amd_decode_mce
notifier_call_chain
atomic_notifier_call_chain
mce_log
machine_check_poll
mce_timer_fn
? mce_cpu_restart
call_timer_fn.isra.29
run_timer_softirq
__do_softirq
irq_exit
smp_apic_timer_interrupt
apic_timer_interrupt
<EOI>
? down_read_trylock
__do_page_fault
? __schedule
do_page_fault
page_fault

Signed-off-by: Daniel J Blueman <daniel@numascale.com>
Link: http://lkml.kernel.org/r/1424144078-24589-1-git-send-email-daniel@numascale.com
[ Boris: massage commit message ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/edac/amd64_edac.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -2174,14 +2174,20 @@ static void __log_bus_error(struct mem_c

static inline void decode_bus_error(int node_id, struct mce *m)
{
- struct mem_ctl_info *mci = mcis[node_id];
- struct amd64_pvt *pvt = mci->pvt_info;
+ struct mem_ctl_info *mci;
+ struct amd64_pvt *pvt;
u8 ecc_type = (m->status >> 45) & 0x3;
u8 xec = XEC(m->status, 0x1f);
u16 ec = EC(m->status);
u64 sys_addr;
struct err_info err;

+ mci = edac_mc_find(node_id);
+ if (!mci)
+ return;
+
+ pvt = mci->pvt_info;
+
/* Bail out early if this was an 'observed' error */
if (PP(ec) == NBSL_PP_OBS)
return;