[PATCH v2] x86: Prevent oops with >16 memory controllers
From: Daniel J Blueman
Date: Mon Feb 16 2015 - 22:37:59 EST
When ECC interrupts occur on memory controllers after EDAC_MAX_MCS (16), the
kernel fatally dereferences unallocated structures [1]; this occurs on at
least NumaConnect systems.
Fix by checking if a memory controller info structure was found; candidate for
stable.
v1->2: Use edac_mc_find() as per Boris's suggestion
Signed-off-by: Daniel J Blueman <daniel@xxxxxxxxxxxxx>
-- [1]
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>
[<ffffffff810e4f9a>] ? vprintk_default+0x1a/0x20
[<ffffffff81b375b9>] ? printk+0x41/0x43
[<ffffffff819f65ff>] amd_decode_mce+0x58f/0x8e0
[<ffffffff810c79ed>] notifier_call_chain+0x4d/0x80
[<ffffffff810c7a45>] atomic_notifier_call_chain+0x15/0x20
[<ffffffff8105352d>] mce_log+0x1d/0x130
[<ffffffff810537d4>] machine_check_poll+0x194/0x260
[<ffffffff81053ae6>] mce_timer_fn+0x116/0x140
[<ffffffff810539d0>] ? mce_cpu_restart+0x40/0x40
[<ffffffff810f17e7>] call_timer_fn.isra.29+0x17/0x80
[<ffffffff810f1a9b>] run_timer_softirq+0x18b/0x220
[<ffffffff810afbb9>] __do_softirq+0xf9/0x200
[<ffffffff810afde6>] irq_exit+0x76/0xa0
[<ffffffff8105dfc1>] smp_apic_timer_interrupt+0x41/0x50
[<ffffffff81b49067>] apic_timer_interrupt+0x67/0x70
<EOI>
[<ffffffff810dfd05>] ? down_read_trylock+0x15/0x20
[<ffffffff8106901b>] __do_page_fault+0xbb/0x4c0
[<ffffffff81b4447a>] ? __schedule+0x25a/0x850
[<ffffffff8106945c>] do_page_fault+0xc/0x10
[<ffffffff81b4977f>] page_fault+0x1f/0x30
---
drivers/edac/amd64_edac.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 17638d7..e8325e5 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -2174,14 +2174,20 @@ static void __log_bus_error(struct mem_ctl_info *mci, struct err_info *err,
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 = edac_mc_find(node_id);
+ 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;
+ /* Unable to decode where no memory controller info is allocated (>EDAC_MAX_MCS) */
+ if (!mci)
+ return;
+
+ pvt = mci->pvt_info;
+
/* Bail out early if this was an 'observed' error */
if (PP(ec) == NBSL_PP_OBS)
return;
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/