The following commit has been merged in the linux branch: commit 70f5dc514c0b183ee813dc3b3983b04891fd1e7a Author: Martin Schwidefsky schwidefsky@de.ibm.com Date: Thu Oct 29 15:04:12 2009 +0100

[S390] cputime: fix overflow on 31 bit systems

The cputime_to_msecs / cputime_to_clock_t and cputime64_to_clock_t cause fixpoint divide exceptions if the cputime is too large. On a machine that collected 49.7 days worth of idle time reading from /proc/stat will generate oopses like this:

Kernel BUG at 001b0c92 [verbose debug info unavailable] fixpoint divide exception: 0009 [#13] SMP Modules linked in: ipv6 CPU: 1 Tainted: G D 2.6.27.10 #5 Process cat (pid: 21352, task: 1fb34138, ksp: 1d2a3d98) Krnl PSW : 070c2000 801b0c92 (show_stat+0x2ca/0x68c) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 Krnl GPRS: 00000001 00001388 00000bb8 0015d2a1 00000000 00000000 000003e8 0001fd91 00000000 00000000 0000129d eecd2ff0 1cc533b9 0036f780 801b0bce 1d2a3cc0 Krnl Code: 801b0c86: f18890abf198 mvo 171(9,%r9),408(9,%r15) 801b0c8c: 98abf170 lm %r10,%r11,368(%r15) 801b0c90: 1da1 dr %r10,%r1 >801b0c92: 90abf170 stm %r10,%r11,368(%r15) 801b0c96: 98abf190 lm %r10,%r11,400(%r15) 801b0c9a: 1da1 dr %r10,%r1 801b0c9c: 90abf190 stm %r10,%r11,400(%r15) 801b0ca0: 18a3 lr %r10,%r3 Call Trace: ([<00000000001b09f4>] show_stat+0x2c/0x68c) [<000000000018dcee>] seq_read+0xb2/0x364 [<00000000001a9980>] proc_reg_read+0x68/0x98 [<00000000001705ee>] vfs_read+0x6e/0xe8 [<0000000000170732>] sys_read+0x36/0x78 [<000000000010f750>] sysc_do_restart+0x12/0x16 [<0000000077f3ad6a>] 0x77f3ad6a <4>---[ end trace 1436ea9559d3de9e ]---

Reported-by: Mike Frysinger vapier@gentoo.org Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com

diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h index 24b1244..f23961a 100644 --- a/arch/s390/include/asm/cputime.h +++ b/arch/s390/include/asm/cputime.h @@ -78,7 +78,7 @@ cputime64_to_jiffies64(cputime64_t cputime) static inline unsigned int cputime_to_msecs(const cputime_t cputime) { - return __div(cputime, 4096000); + return cputime_div(cputime, 4096000); }

static inline cputime_t @@ -160,7 +160,7 @@ cputime_to_timeval(const cputime_t cputime, struct timeval *value) static inline clock_t cputime_to_clock_t(cputime_t cputime) { - return __div(cputime, 4096000000ULL / USER_HZ); + return cputime_div(cputime, 4096000000ULL / USER_HZ); }

static inline cputime_t @@ -175,7 +175,7 @@ clock_t_to_cputime(unsigned long x) static inline clock_t cputime64_to_clock_t(cputime64_t cputime) { - return __div(cputime, 4096000000ULL / USER_HZ); + return cputime_div(cputime, 4096000000ULL / USER_HZ); }

struct s390_idle_data {