[PATCH 4.1 031/123] s390/cachinfo: add missing facility check to init_cache_level()

From: Greg Kroah-Hartman
Date: Sat Aug 08 2015 - 18:35:16 EST

4.1-stable review patch. If anyone has any objections, please let me know.


From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>

commit 0b991f5cdcd6201e5401f83ca3a672343c3bfc49 upstream.

Stephen Powell reported the following crash on a z890 machine:

Kernel BUG at 00000000001219d0 [verbose debug info unavailable]
illegal operation: 0001 ilc:3 [#1] SMP
Krnl PSW : 0704e00180000000 00000000001219d0 (init_cache_level+0x38/0xe0)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 EA:3
Krnl Code: 00000000001219c2: a7840056 brc 8,121a6e
00000000001219c6: a7190000 lghi %r1,0
#00000000001219ca: eb101000004c ecag %r1,%r0,0(%r1)
>00000000001219d0: a7390000 lghi %r3,0
00000000001219d4: e310f0a00024 stg %r1,160(%r15)
00000000001219da: a7080000 lhi %r0,0
00000000001219de: a7b9f000 lghi %r11,-4096
00000000001219e2: c0a0002899d9 larl %r10,634d94
Call Trace:
[<0000000000478ee2>] detect_cache_attributes+0x2a/0x2b8
[<000000000097c9b0>] cacheinfo_sysfs_init+0x60/0xc8
[<00000000001001c0>] do_one_initcall+0x98/0x1c8
[<000000000094fdc2>] kernel_init_freeable+0x212/0x2d8
[<000000000062352e>] kernel_init+0x26/0x118
[<000000000062fd2e>] kernel_thread_starter+0x6/0xc

The illegal operation was executed because of a missing facility check,
which should have made sure that the ECAG execution would only be executed
on machines which have the general-instructions-extension facility

Reported-and-tested-by: Stephen Powell <zlinuxman@xxxxxxxxxx>
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/s390/kernel/cache.c | 2 ++
1 file changed, 2 insertions(+)

--- a/arch/s390/kernel/cache.c
+++ b/arch/s390/kernel/cache.c
@@ -138,6 +138,8 @@ int init_cache_level(unsigned int cpu)
union cache_topology ct;
enum cache_type ctype;

+ if (!test_facility(34))
+ return -EOPNOTSUPP;
if (!this_cpu_ci)
return -EINVAL;
ct.raw = ecag(EXTRACT_TOPOLOGY, 0, 0);

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/