Messages in this thread | | | Date | Mon, 5 Jan 2009 18:15:06 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [BUG] NULL pointer deref with rcutorture |
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On Mon, Jan 05, 2009 at 04:29:12PM -0800, Paul E. McKenney wrote: > On Mon, Jan 05, 2009 at 02:18:36PM -0800, Paul E. McKenney wrote: > > On Mon, Jan 05, 2009 at 09:31:53PM +0100, Eric Sesterhenn wrote: > > > * Paul E. McKenney (paulmck@linux.vnet.ibm.com) wrote: > > > > On Mon, Jan 05, 2009 at 09:01:45PM +0100, Eric Sesterhenn wrote: > > > > > hi, > > > > > > > > > > * Paul E. McKenney (paulmck@linux.vnet.ibm.com) wrote: > > > > > > On Mon, Jan 05, 2009 at 07:56:55PM +0100, Eric Sesterhenn wrote: > > > > > > > > > > > > Wow!!! Am I reading this correctly? Does the above "call" instruction > > > > > > -really- call one byte into itself? That is what the hex for the x86 > > > > > > instruction -looks- like it is doing, but I cannot see what would have > > > > > > possessed the compiler to generate this code. > > > > > > > > > > Compiler is gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu3) > > > > > > > > I am using 4.1.3, for whatever it is worth. (Ancient, I know!) > > > > > > > > > > When I compile on a 32-bit x86 machine, I don't see the above "call" > > > > > > instruction. Other than that, the code I see looks consistent. > > > > > > > > > > > > > 9f0: eb 1d jmp a0f <rcu_stutter_wait+0x27> > > > > > > > 9f2: 83 3d 00 00 00 00 00 cmpl $0x0,0x0 > > > > > > > 9f9: b8 01 00 00 00 mov $0x1,%eax > > > > > > > 9fe: 75 0a jne a0a <rcu_stutter_wait+0x22> > > > > > > > a00: b8 e8 03 00 00 mov $0x3e8,%eax > > > > > > > a05: e8 fc ff ff ff call a06 <rcu_stutter_wait+0x1e> > > > > > > > a0a: e8 fc ff ff ff call a0b <rcu_stutter_wait+0x23> > > > > > > > a0f: 83 3d 6c 00 00 00 00 cmpl $0x0,0x6c > > > > > > > ^---------- this line > > > > > > > > > > > > This looks like the first test in the "while" loop. > > > > > > > > > > > > > a16: 75 09 jne a21 <rcu_stutter_wait+0x39> > > > > > > > a18: 83 3d 00 00 00 00 00 cmpl $0x0,0x0 > > > > > > > a1f: 75 09 jne a2a <rcu_stutter_wait+0x42> > > > > > > > a21: 83 3d 50 1a 00 00 00 cmpl $0x0,0x1a50 > > > > > > > a28: 74 c8 je 9f2 <rcu_stutter_wait+0xa> > > > > > > > a2a: 5d pop %ebp > > > > > > > a2b: c3 ret > > > > > > > > > > > > The corresponding C code is as follows: > > > > > > > > > > > > static void > > > > > > rcu_stutter_wait(void) > > > > > > { > > > > > > while ((stutter_pause_test || !rcutorture_runnable) && !fullstop) { > > > > > > if (rcutorture_runnable) > > > > > > schedule_timeout_interruptible(1); > > > > > > else > > > > > > schedule_timeout_interruptible(round_jiffies_relative(HZ)); > > > > > > } > > > > > > } > > > > > > > > > > > > I don't see much opportunity for a page fault here... This is the > > > > > > binary I get when I compile it, though not as a module: > > > > > > > > > > > > 0000085a <rcu_stutter_wait>: > > > > > > 85a: 55 push %ebp > > > > > > 85b: 89 e5 mov %esp,%ebp > > > > > > 85d: eb 1d jmp 87c <rcu_stutter_wait+0x22> > > > > > > 85f: 83 3d 00 00 00 00 00 cmpl $0x0,0x0 > > > > > > 866: b8 01 00 00 00 mov $0x1,%eax > > > > > > 86b: 75 0a jne 877 <rcu_stutter_wait+0x1d> > > > > > > 86d: b8 e8 03 00 00 mov $0x3e8,%eax > > > > > > 872: e8 fc ff ff ff call 873 <rcu_stutter_wait+0x19> > > > > > > 877: e8 fc ff ff ff call 878 <rcu_stutter_wait+0x1e> > > > > > > 87c: 83 3d 14 00 00 00 00 cmpl $0x0,0x14 > > > > > > 883: 75 09 jne 88e <rcu_stutter_wait+0x34> > > > > > > 885: 83 3d 00 00 00 00 00 cmpl $0x0,0x0 > > > > > > 88c: 75 09 jne 897 <rcu_stutter_wait+0x3d> > > > > > > 88e: 83 3d 08 1a 00 00 00 cmpl $0x0,0x1a08 > > > > > > 895: 74 c8 je 85f <rcu_stutter_wait+0x5> > > > > > > 897: 5d pop %ebp > > > > > > 898: c3 ret > > > > > > > > > > > > I confess, I am confused!!! > > > > > > > > > > on the other box with a different gcc version > > > > > > > > > > gcc version 4.3.2 (Ubuntu 4.3.2-1ubuntu11) > > > > > > > > > > d1902e90 is the start of rcu_stutter_wait > > > > > > > > > > [ 533.391719] d087e000 d1902e90 > > > > > [ 533.392294] rcu-torture:--- Start of test: nreaders=2 nfakewriters=4 stat_interval=0 verbose=0 test_no_idle_hz=0 shuffle_interval=3 stutter=5 irqreader=1 > > > > > [ 541.000139] BUG: unable to handle kernel paging request at d1902efd > > > > > [ 541.000423] IP: [<d1902efd>] 0xd1902efd > > > > > [ 541.000660] *pde = 0f08f067 *pte = 00000000 > > > > > [ 541.000867] Oops: 0000 [#1] DEBUG_PAGEALLOC > > > > > [ 541.001126] last sysfs file: /sys/block/sda/size > > > > > [ 541.001246] Modules linked in: nfsd exportfs nfs lockd nfs_acl auth_rpcgss sunrpc ipv6 fuse unix [last unloaded: rcutorture] > > > > > [ 541.002235] > > > > > [ 541.002334] Pid: 5292, comm: rcu_torture_wri Not tainted (2.6.28 #84) > > > > > [ 541.002470] EIP: 0060:[<d1902efd>] EFLAGS: 00010296 CPU: 0 > > > > > [ 541.002598] EIP is at 0xd1902efd > > > > > [ 541.002767] EAX: 00000000 EBX: d19073c0 ECX: 00000000 EDX: 00000000 > > > > > [ 541.002900] ESI: 0000000a EDI: 00000000 EBP: c7b63fb8 ESP: c7b63fb8 > > > > > [ 541.003033] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 > > > > > [ 541.003160] Process rcu_torture_wri (pid: 5292, ti=c7b63000 task=c7b09710 task.ti=c7b63000) > > > > > [ 541.003400] Stack: > > > > > [ 541.003497] c7b63fd0 d19032c1 00000000 00000000 00000000 d1903200 c7b63fe0 c013d80a > > > > > [ 541.004022] c013d7d0 00000000 00000000 c0103cf3 cef6ee70 00000000 00000000 00000000 > > > > > [ 541.004022] 00000201 000004b4 > > > > > [ 541.004022] Call Trace: > > > > > [ 541.004022] [<c013d80a>] ? kthread+0x3a/0x70 > > > > > [ 541.004022] [<c013d7d0>] ? kthread+0x0/0x70 > > > > > [ 541.004022] [<c0103cf3>] ? kernel_thread_helper+0x7/0x14 > > > > > [ 541.004022] Code: Bad EIP value. > > > > > [ 541.004022] EIP: [<d1902efd>] 0xd1902efd SS:ESP 0068:c7b63fb8 > > > > > [ 541.004022] ---[ end trace cb3b10c2bb94b4e3 ]--- > > > > > > > > > > > > > > > 00000e90 <rcu_stutter_wait>: > > > > > e90: 55 push %ebp > > > > > e91: 89 e5 mov %esp,%ebp > > > > > e93: 90 nop > > > > > e94: 8d 74 26 00 lea 0x0(%esi,%eiz,1),%esi > > > > > e98: a1 98 00 00 00 mov 0x98,%eax > > > > > e9d: 85 c0 test %eax,%eax > > > > > e9f: 75 09 jne eaa <rcu_stutter_wait+0x1a> > > > > > ea1: a1 00 00 00 00 mov 0x0,%eax > > > > > ea6: 85 c0 test %eax,%eax > > > > > ea8: 75 36 jne ee0 <rcu_stutter_wait+0x50> > > > > > eaa: a1 88 1a 00 00 mov 0x1a88,%eax > > > > > eaf: 85 c0 test %eax,%eax > > > > > eb1: 75 2d jne ee0 <rcu_stutter_wait+0x50> > > > > > eb3: 8b 15 00 00 00 00 mov 0x0,%edx > > > > > eb9: 85 d2 test %edx,%edx > > > > > ebb: 74 2b je ee8 <rcu_stutter_wait+0x58> > > > > > ebd: b8 01 00 00 00 mov $0x1,%eax > > > > > ec2: e8 fc ff ff ff call ec3 <rcu_stutter_wait+0x33> > > > > > ec7: a1 98 00 00 00 mov 0x98,%eax > > > > > ecc: 85 c0 test %eax,%eax > > > > > ece: 74 d1 je ea1 <rcu_stutter_wait+0x11> > > > > > ed0: a1 88 1a 00 00 mov 0x1a88,%eax > > > > > ed5: 85 c0 test %eax,%eax > > > > > ed7: 74 da je eb3 <rcu_stutter_wait+0x23> > > > > > ed9: 8d b4 26 00 00 00 00 lea 0x0(%esi,%eiz,1),%esi > > > > > ee0: 5d pop %ebp > > > > > ee1: c3 ret > > > > > ee2: 8d b6 00 00 00 00 lea 0x0(%esi),%esi > > > > > ee8: b8 fa 00 00 00 mov $0xfa,%eax > > > > > eed: e8 fc ff ff ff call eee <rcu_stutter_wait+0x5e> > > > > > > > > Here we are again calling one byte into the current instruction!!! > > > > > > > > Or am I misinterpreting this code? > > > > > > > > > ef2: 8d b6 00 00 00 00 lea 0x0(%esi),%esi > > > > > ef8: e8 fc ff ff ff call ef9 <rcu_stutter_wait+0x69> > > > > > efd: 8d 76 00 lea 0x0(%esi),%esi > > > > > ^------------- here > > > > > > > > > > This one looks more like it can explain a page fault > > > > > > > > I don't understand why there are indirections in the assembly given the > > > > C code for rcu_stutter_wait(). > > > > > > > > > f00: eb 96 jmp e98 <rcu_stutter_wait+0x8> > > > > > f02: 8d b4 26 00 00 00 00 lea 0x0(%esi,%eiz,1),%esi > > > > > f09: 8d bc 27 00 00 00 00 lea 0x0(%edi,%eiz,1),%edi > > > > > > ok, after trying to find out if the ubuntu gccs are broken, i stumbled > > > upon this: > > > http://forum.soft32.com/linux/Strange-problem-disassembling-shared-lib-ftopict439936.html > > > > > > Seems the difference is that you dont compile it as a module and the > > > jump is perfectly normal, it gets overwritten when the stuff is loaded > > > objdump -dr gives me > > > > > > 00000e90 <rcu_stutter_wait>: > > > e90: 55 push %ebp > > > e91: 89 e5 mov %esp,%ebp > > > e93: 90 nop > > > e94: 8d 74 26 00 lea 0x0(%esi,%eiz,1),%esi > > > e98: a1 98 00 00 00 mov 0x98,%eax > > > e99: R_386_32 .bss > > > e9d: 85 c0 test %eax,%eax > > > e9f: 75 09 jne eaa <rcu_stutter_wait+0x1a> > > > ea1: a1 00 00 00 00 mov 0x0,%eax > > > ea2: R_386_32 rcutorture_runnable > > > ea6: 85 c0 test %eax,%eax > > > ea8: 75 36 jne ee0 <rcu_stutter_wait+0x50> > > > eaa: a1 88 1a 00 00 mov 0x1a88,%eax > > > eab: R_386_32 .bss > > > eaf: 85 c0 test %eax,%eax > > > eb1: 75 2d jne ee0 <rcu_stutter_wait+0x50> > > > eb3: 8b 15 00 00 00 00 mov 0x0,%edx > > > eb5: R_386_32 rcutorture_runnable > > > eb9: 85 d2 test %edx,%edx > > > ebb: 74 2b je ee8 <rcu_stutter_wait+0x58> > > > ebd: b8 01 00 00 00 mov $0x1,%eax > > > ec2: e8 fc ff ff ff call ec3 <rcu_stutter_wait+0x33> > > > ec3: R_386_PC32 schedule_timeout_interruptible > > > ec7: a1 98 00 00 00 mov 0x98,%eax > > > ec8: R_386_32 .bss > > > ecc: 85 c0 test %eax,%eax > > > ece: 74 d1 je ea1 <rcu_stutter_wait+0x11> > > > ed0: a1 88 1a 00 00 mov 0x1a88,%eax > > > ed1: R_386_32 .bss > > > ed5: 85 c0 test %eax,%eax > > > ed7: 74 da je eb3 <rcu_stutter_wait+0x23> > > > ed9: 8d b4 26 00 00 00 00 lea 0x0(%esi,%eiz,1),%esi > > > ee0: 5d pop %ebp > > > ee1: c3 ret > > > ee2: 8d b6 00 00 00 00 lea 0x0(%esi),%esi > > > ee8: b8 fa 00 00 00 mov $0xfa,%eax > > > eed: e8 fc ff ff ff call eee <rcu_stutter_wait+0x5e> > > > eee: R_386_PC32 round_jiffies_relative > > > ef2: 8d b6 00 00 00 00 lea 0x0(%esi),%esi > > > ef8: e8 fc ff ff ff call ef9 <rcu_stutter_wait+0x69> > > > ef9: R_386_PC32 schedule_timeout_interruptible > > > efd: 8d 76 00 lea 0x0(%esi),%esi > > > > > > here is the deref ------------------------^ > > > > Ah!!! We are getting a page fault while cleaning up the stack frame? > > > > Ouch! > > > > > f00: eb 96 jmp e98 <rcu_stutter_wait+0x8> > > > f02: 8d b4 26 00 00 00 00 lea 0x0(%esi,%eiz,1),%esi > > > f09: 8d bc 27 00 00 00 00 lea 0x0(%edi,%eiz,1),%edi > > And now I can run this. gcc v3.4.4 gives yet a different error: > > divide error: 0000 [#1] PREEMPT SMP > last sysfs file: /sys/devices/pci0000:00/0000:00:0a.0/0000:02:04.0/host0/target0:0:6/0:0:6:0/type > CPU 1 > Modules linked in: [last unloaded: rcutorture] > Pid: 3369, comm: rcu_torture_rea Not tainted 2.6.28-autokern1 #1 > RIP: 0010:[<ffffffffa0000142>] [<ffffffffa0000142>] 0xffffffffa0000142 > RSP: 0000:ffff88007f0afeb0 EFLAGS: 00010246 > RAX: 00000000def36d6a RBX: ffffffffa0006850 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffff88007ecf1600 RDI: ffff88007f0afef0 > RBP: 0000000000000dd4 R08: ffff88007f0ae000 R09: ffffffff8037c7d9 > R10: 0000000000000000 R11: ffffffff8037c7d9 R12: 0000000000000000 > R13: 000000000000000a R14: 0000000000000000 R15: 0000000000000000 > FS: 0000000000000000(0000) GS:ffff8800e3801c00(0000) knlGS:00000000f7f3ab80 > CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > CR2: 00000000080dc87c CR3: 0000000000201000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process rcu_torture_rea (pid: 3369, threadinfo ffff88007f0ae000, task ffff88007ecf5d80) > Stack: > ffffffff8037c7d9 ffffffffa000090d ffff88007ecfdec0 ffff88007ec17eb0 > 0000000000000001 ffffffffa00006e6 0000000000000000 ffff8800e3488000 > c744ca136d6adef3 0000000000000256 0000000000000000 ffffffffa0000807 > Call Trace: > [<ffffffff8037c7d9>] ? delay_tsc+0x0/0x99 > [<ffffffff80245b94>] ? kthread+0x3d/0x63 > [<ffffffff8020c3ea>] ? child_rip+0xa/0x20 > [<ffffffff80245b57>] ? kthread+0x0/0x63 > [<ffffffff8020c3e0>] ? child_rip+0x0/0x20 > Code: 58 c3 56 bf 01 00 00 00 e8 88 bd 22 e0 59 31 c0 c3 41 51 e8 69 ff ff ff 48 63 15 0a 58 00 00 48 69 d2 90 01 00 00 48 89 d1 31 d2 <48> f7 f1 48 85 d2 75 0c 41 58 bf 78 1b 0d 00 e9 32 c7 37 e0 5f > RIP [<ffffffffa0000142>] 0xffffffffa0000142 > RSP <ffff88007f0afeb0> > > I will see what I can find from this.
Hello, Eric,
Just for grins, I built the 2.6.28 kernel/rcutorture.c on b58602a. It insmoded and rmmoded without errors.
Could you please try this on your setup? I have attached this file in case that helps.
Thanx, Paul /* * Read-Copy Update module-based torture test facility * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * Copyright (C) IBM Corporation, 2005, 2006 * * Authors: Paul E. McKenney <paulmck@us.ibm.com> * Josh Triplett <josh@freedesktop.org> * * See also: Documentation/RCU/torture.txt */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/kthread.h> #include <linux/err.h> #include <linux/spinlock.h> #include <linux/smp.h> #include <linux/rcupdate.h> #include <linux/interrupt.h> #include <linux/sched.h> #include <asm/atomic.h> #include <linux/bitops.h> #include <linux/completion.h> #include <linux/moduleparam.h> #include <linux/percpu.h> #include <linux/notifier.h> #include <linux/freezer.h> #include <linux/cpu.h> #include <linux/delay.h> #include <linux/stat.h> #include <linux/srcu.h> #include <linux/slab.h> #include <asm/byteorder.h>
MODULE_LICENSE("GPL"); MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and " "Josh Triplett <josh@freedesktop.org>");
static int nreaders = -1; /* # reader threads, defaults to 2*ncpus */ static int nfakewriters = 4; /* # fake writer threads */ static int stat_interval; /* Interval between stats, in seconds. */ /* Defaults to "only at end of test". */ static int verbose; /* Print more debug info. */ static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */ static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/ static int stutter = 5; /* Start/stop testing interval (in sec) */ static int irqreader = 1; /* RCU readers from irq (timers). */ static char *torture_type = "rcu"; /* What RCU implementation to torture. */
module_param(nreaders, int, 0444); MODULE_PARM_DESC(nreaders, "Number of RCU reader threads"); module_param(nfakewriters, int, 0444); MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads"); module_param(stat_interval, int, 0444); MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s"); module_param(verbose, bool, 0444); MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s"); module_param(test_no_idle_hz, bool, 0444); MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs"); module_param(shuffle_interval, int, 0444); MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles"); module_param(stutter, int, 0444); MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test"); module_param(irqreader, int, 0444); MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers"); module_param(torture_type, charp, 0444); MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
#define TORTURE_FLAG "-torture:" #define PRINTK_STRING(s) \ do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0) #define VERBOSE_PRINTK_STRING(s) \ do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0) #define VERBOSE_PRINTK_ERRSTRING(s) \ do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
static char printk_buf[4096];
static int nrealreaders; static struct task_struct *writer_task; static struct task_struct **fakewriter_tasks; static struct task_struct **reader_tasks; static struct task_struct *stats_task; static struct task_struct *shuffler_task; static struct task_struct *stutter_task;
#define RCU_TORTURE_PIPE_LEN 10
struct rcu_torture { struct rcu_head rtort_rcu; int rtort_pipe_count; struct list_head rtort_free; int rtort_mbtest; };
static int fullstop = 0; /* stop generating callbacks at test end. */ static LIST_HEAD(rcu_torture_freelist); static struct rcu_torture *rcu_torture_current = NULL; static long rcu_torture_current_version = 0; static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; static DEFINE_SPINLOCK(rcu_torture_lock); static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = { 0 }; static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) = { 0 }; static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; static atomic_t n_rcu_torture_alloc; static atomic_t n_rcu_torture_alloc_fail; static atomic_t n_rcu_torture_free; static atomic_t n_rcu_torture_mberror; static atomic_t n_rcu_torture_error; static long n_rcu_torture_timers = 0; static struct list_head rcu_torture_removed;
static int stutter_pause_test = 0;
#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE) #define RCUTORTURE_RUNNABLE_INIT 1 #else #define RCUTORTURE_RUNNABLE_INIT 0 #endif int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
/* * Allocate an element from the rcu_tortures pool. */ static struct rcu_torture * rcu_torture_alloc(void) { struct list_head *p;
spin_lock_bh(&rcu_torture_lock); if (list_empty(&rcu_torture_freelist)) { atomic_inc(&n_rcu_torture_alloc_fail); spin_unlock_bh(&rcu_torture_lock); return NULL; } atomic_inc(&n_rcu_torture_alloc); p = rcu_torture_freelist.next; list_del_init(p); spin_unlock_bh(&rcu_torture_lock); return container_of(p, struct rcu_torture, rtort_free); }
/* * Free an element to the rcu_tortures pool. */ static void rcu_torture_free(struct rcu_torture *p) { atomic_inc(&n_rcu_torture_free); spin_lock_bh(&rcu_torture_lock); list_add_tail(&p->rtort_free, &rcu_torture_freelist); spin_unlock_bh(&rcu_torture_lock); }
struct rcu_random_state { unsigned long rrs_state; long rrs_count; };
#define RCU_RANDOM_MULT 39916801 /* prime */ #define RCU_RANDOM_ADD 479001701 /* prime */ #define RCU_RANDOM_REFRESH 10000
#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
/* * Crude but fast random-number generator. Uses a linear congruential * generator, with occasional help from cpu_clock(). */ static unsigned long rcu_random(struct rcu_random_state *rrsp) { if (--rrsp->rrs_count < 0) { rrsp->rrs_state += (unsigned long)cpu_clock(raw_smp_processor_id()); rrsp->rrs_count = RCU_RANDOM_REFRESH; } rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD; return swahw32(rrsp->rrs_state); }
static void rcu_stutter_wait(void) { while (stutter_pause_test || !rcutorture_runnable) if (rcutorture_runnable) schedule_timeout_interruptible(1); else schedule_timeout_interruptible(round_jiffies_relative(HZ)); }
/* * Operations vector for selecting different types of tests. */
struct rcu_torture_ops { void (*init)(void); void (*cleanup)(void); int (*readlock)(void); void (*readdelay)(struct rcu_random_state *rrsp); void (*readunlock)(int idx); int (*completed)(void); void (*deferredfree)(struct rcu_torture *p); void (*sync)(void); void (*cb_barrier)(void); int (*stats)(char *page); int irqcapable; char *name; }; static struct rcu_torture_ops *cur_ops = NULL;
/* * Definitions for rcu torture testing. */
static int rcu_torture_read_lock(void) __acquires(RCU) { rcu_read_lock(); return 0; }
static void rcu_read_delay(struct rcu_random_state *rrsp) { long delay; const long longdelay = 200;
/* We want there to be long-running readers, but not all the time. */
delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay); if (!delay) udelay(longdelay); }
static void rcu_torture_read_unlock(int idx) __releases(RCU) { rcu_read_unlock(); }
static int rcu_torture_completed(void) { return rcu_batches_completed(); }
static void rcu_torture_cb(struct rcu_head *p) { int i; struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
if (fullstop) { /* Test is ending, just drop callbacks on the floor. */ /* The next initialization will pick up the pieces. */ return; } i = rp->rtort_pipe_count; if (i > RCU_TORTURE_PIPE_LEN) i = RCU_TORTURE_PIPE_LEN; atomic_inc(&rcu_torture_wcount[i]); if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { rp->rtort_mbtest = 0; rcu_torture_free(rp); } else cur_ops->deferredfree(rp); }
static void rcu_torture_deferred_free(struct rcu_torture *p) { call_rcu(&p->rtort_rcu, rcu_torture_cb); }
static struct rcu_torture_ops rcu_ops = { .init = NULL, .cleanup = NULL, .readlock = rcu_torture_read_lock, .readdelay = rcu_read_delay, .readunlock = rcu_torture_read_unlock, .completed = rcu_torture_completed, .deferredfree = rcu_torture_deferred_free, .sync = synchronize_rcu, .cb_barrier = rcu_barrier, .stats = NULL, .irqcapable = 1, .name = "rcu" };
static void rcu_sync_torture_deferred_free(struct rcu_torture *p) { int i; struct rcu_torture *rp; struct rcu_torture *rp1;
cur_ops->sync(); list_add(&p->rtort_free, &rcu_torture_removed); list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { i = rp->rtort_pipe_count; if (i > RCU_TORTURE_PIPE_LEN) i = RCU_TORTURE_PIPE_LEN; atomic_inc(&rcu_torture_wcount[i]); if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { rp->rtort_mbtest = 0; list_del(&rp->rtort_free); rcu_torture_free(rp); } } }
static void rcu_sync_torture_init(void) { INIT_LIST_HEAD(&rcu_torture_removed); }
static struct rcu_torture_ops rcu_sync_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = rcu_torture_read_lock, .readdelay = rcu_read_delay, .readunlock = rcu_torture_read_unlock, .completed = rcu_torture_completed, .deferredfree = rcu_sync_torture_deferred_free, .sync = synchronize_rcu, .cb_barrier = NULL, .stats = NULL, .irqcapable = 1, .name = "rcu_sync" };
/* * Definitions for rcu_bh torture testing. */
static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH) { rcu_read_lock_bh(); return 0; }
static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH) { rcu_read_unlock_bh(); }
static int rcu_bh_torture_completed(void) { return rcu_batches_completed_bh(); }
static void rcu_bh_torture_deferred_free(struct rcu_torture *p) { call_rcu_bh(&p->rtort_rcu, rcu_torture_cb); }
struct rcu_bh_torture_synchronize { struct rcu_head head; struct completion completion; };
static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head) { struct rcu_bh_torture_synchronize *rcu;
rcu = container_of(head, struct rcu_bh_torture_synchronize, head); complete(&rcu->completion); }
static void rcu_bh_torture_synchronize(void) { struct rcu_bh_torture_synchronize rcu;
init_completion(&rcu.completion); call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb); wait_for_completion(&rcu.completion); }
static struct rcu_torture_ops rcu_bh_ops = { .init = NULL, .cleanup = NULL, .readlock = rcu_bh_torture_read_lock, .readdelay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = rcu_bh_torture_read_unlock, .completed = rcu_bh_torture_completed, .deferredfree = rcu_bh_torture_deferred_free, .sync = rcu_bh_torture_synchronize, .cb_barrier = rcu_barrier_bh, .stats = NULL, .irqcapable = 1, .name = "rcu_bh" };
static struct rcu_torture_ops rcu_bh_sync_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = rcu_bh_torture_read_lock, .readdelay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = rcu_bh_torture_read_unlock, .completed = rcu_bh_torture_completed, .deferredfree = rcu_sync_torture_deferred_free, .sync = rcu_bh_torture_synchronize, .cb_barrier = NULL, .stats = NULL, .irqcapable = 1, .name = "rcu_bh_sync" };
/* * Definitions for srcu torture testing. */
static struct srcu_struct srcu_ctl;
static void srcu_torture_init(void) { init_srcu_struct(&srcu_ctl); rcu_sync_torture_init(); }
static void srcu_torture_cleanup(void) { synchronize_srcu(&srcu_ctl); cleanup_srcu_struct(&srcu_ctl); }
static int srcu_torture_read_lock(void) __acquires(&srcu_ctl) { return srcu_read_lock(&srcu_ctl); }
static void srcu_read_delay(struct rcu_random_state *rrsp) { long delay; const long uspertick = 1000000 / HZ; const long longdelay = 10;
/* We want there to be long-running readers, but not all the time. */
delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick); if (!delay) schedule_timeout_interruptible(longdelay); }
static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl) { srcu_read_unlock(&srcu_ctl, idx); }
static int srcu_torture_completed(void) { return srcu_batches_completed(&srcu_ctl); }
static void srcu_torture_synchronize(void) { synchronize_srcu(&srcu_ctl); }
static int srcu_torture_stats(char *page) { int cnt = 0; int cpu; int idx = srcu_ctl.completed & 0x1;
cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):", torture_type, TORTURE_FLAG, idx); for_each_possible_cpu(cpu) { cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu, per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx], per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]); } cnt += sprintf(&page[cnt], "\n"); return cnt; }
static struct rcu_torture_ops srcu_ops = { .init = srcu_torture_init, .cleanup = srcu_torture_cleanup, .readlock = srcu_torture_read_lock, .readdelay = srcu_read_delay, .readunlock = srcu_torture_read_unlock, .completed = srcu_torture_completed, .deferredfree = rcu_sync_torture_deferred_free, .sync = srcu_torture_synchronize, .cb_barrier = NULL, .stats = srcu_torture_stats, .name = "srcu" };
/* * Definitions for sched torture testing. */
static int sched_torture_read_lock(void) { preempt_disable(); return 0; }
static void sched_torture_read_unlock(int idx) { preempt_enable(); }
static int sched_torture_completed(void) { return 0; }
static void rcu_sched_torture_deferred_free(struct rcu_torture *p) { call_rcu_sched(&p->rtort_rcu, rcu_torture_cb); }
static void sched_torture_synchronize(void) { synchronize_sched(); }
static struct rcu_torture_ops sched_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = sched_torture_read_lock, .readdelay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, .completed = sched_torture_completed, .deferredfree = rcu_sched_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = rcu_barrier_sched, .stats = NULL, .irqcapable = 1, .name = "sched" };
static struct rcu_torture_ops sched_ops_sync = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = sched_torture_read_lock, .readdelay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, .completed = sched_torture_completed, .deferredfree = rcu_sync_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = NULL, .stats = NULL, .name = "sched_sync" };
/* * RCU torture writer kthread. Repeatedly substitutes a new structure * for that pointed to by rcu_torture_current, freeing the old structure * after a series of grace periods (the "pipeline"). */ static int rcu_torture_writer(void *arg) { int i; long oldbatch = rcu_batches_completed(); struct rcu_torture *rp; struct rcu_torture *old_rp; static DEFINE_RCU_RANDOM(rand);
VERBOSE_PRINTK_STRING("rcu_torture_writer task started"); set_user_nice(current, 19);
do { schedule_timeout_uninterruptible(1); if ((rp = rcu_torture_alloc()) == NULL) continue; rp->rtort_pipe_count = 0; udelay(rcu_random(&rand) & 0x3ff); old_rp = rcu_torture_current; rp->rtort_mbtest = 1; rcu_assign_pointer(rcu_torture_current, rp); smp_wmb(); if (old_rp) { i = old_rp->rtort_pipe_count; if (i > RCU_TORTURE_PIPE_LEN) i = RCU_TORTURE_PIPE_LEN; atomic_inc(&rcu_torture_wcount[i]); old_rp->rtort_pipe_count++; cur_ops->deferredfree(old_rp); } rcu_torture_current_version++; oldbatch = cur_ops->completed(); rcu_stutter_wait(); } while (!kthread_should_stop() && !fullstop); VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping"); while (!kthread_should_stop()) schedule_timeout_uninterruptible(1); return 0; }
/* * RCU torture fake writer kthread. Repeatedly calls sync, with a random * delay between calls. */ static int rcu_torture_fakewriter(void *arg) { DEFINE_RCU_RANDOM(rand);
VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started"); set_user_nice(current, 19);
do { schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10); udelay(rcu_random(&rand) & 0x3ff); cur_ops->sync(); rcu_stutter_wait(); } while (!kthread_should_stop() && !fullstop);
VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping"); while (!kthread_should_stop()) schedule_timeout_uninterruptible(1); return 0; }
/* * RCU torture reader from timer handler. Dereferences rcu_torture_current, * incrementing the corresponding element of the pipeline array. The * counter in the element should never be greater than 1, otherwise, the * RCU implementation is broken. */ static void rcu_torture_timer(unsigned long unused) { int idx; int completed; static DEFINE_RCU_RANDOM(rand); static DEFINE_SPINLOCK(rand_lock); struct rcu_torture *p; int pipe_count;
idx = cur_ops->readlock(); completed = cur_ops->completed(); p = rcu_dereference(rcu_torture_current); if (p == NULL) { /* Leave because rcu_torture_writer is not yet underway */ cur_ops->readunlock(idx); return; } if (p->rtort_mbtest == 0) atomic_inc(&n_rcu_torture_mberror); spin_lock(&rand_lock); cur_ops->readdelay(&rand); n_rcu_torture_timers++; spin_unlock(&rand_lock); preempt_disable(); pipe_count = p->rtort_pipe_count; if (pipe_count > RCU_TORTURE_PIPE_LEN) { /* Should not happen, but... */ pipe_count = RCU_TORTURE_PIPE_LEN; } ++__get_cpu_var(rcu_torture_count)[pipe_count]; completed = cur_ops->completed() - completed; if (completed > RCU_TORTURE_PIPE_LEN) { /* Should not happen, but... */ completed = RCU_TORTURE_PIPE_LEN; } ++__get_cpu_var(rcu_torture_batch)[completed]; preempt_enable(); cur_ops->readunlock(idx); }
/* * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, * incrementing the corresponding element of the pipeline array. The * counter in the element should never be greater than 1, otherwise, the * RCU implementation is broken. */ static int rcu_torture_reader(void *arg) { int completed; int idx; DEFINE_RCU_RANDOM(rand); struct rcu_torture *p; int pipe_count; struct timer_list t;
VERBOSE_PRINTK_STRING("rcu_torture_reader task started"); set_user_nice(current, 19); if (irqreader && cur_ops->irqcapable) setup_timer_on_stack(&t, rcu_torture_timer, 0);
do { if (irqreader && cur_ops->irqcapable) { if (!timer_pending(&t)) mod_timer(&t, 1); } idx = cur_ops->readlock(); completed = cur_ops->completed(); p = rcu_dereference(rcu_torture_current); if (p == NULL) { /* Wait for rcu_torture_writer to get underway */ cur_ops->readunlock(idx); schedule_timeout_interruptible(HZ); continue; } if (p->rtort_mbtest == 0) atomic_inc(&n_rcu_torture_mberror); cur_ops->readdelay(&rand); preempt_disable(); pipe_count = p->rtort_pipe_count; if (pipe_count > RCU_TORTURE_PIPE_LEN) { /* Should not happen, but... */ pipe_count = RCU_TORTURE_PIPE_LEN; } ++__get_cpu_var(rcu_torture_count)[pipe_count]; completed = cur_ops->completed() - completed; if (completed > RCU_TORTURE_PIPE_LEN) { /* Should not happen, but... */ completed = RCU_TORTURE_PIPE_LEN; } ++__get_cpu_var(rcu_torture_batch)[completed]; preempt_enable(); cur_ops->readunlock(idx); schedule(); rcu_stutter_wait(); } while (!kthread_should_stop() && !fullstop); VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping"); if (irqreader && cur_ops->irqcapable) del_timer_sync(&t); while (!kthread_should_stop()) schedule_timeout_uninterruptible(1); return 0; }
/* * Create an RCU-torture statistics message in the specified buffer. */ static int rcu_torture_printk(char *page) { int cnt = 0; int cpu; int i; long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
for_each_possible_cpu(cpu) { for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i]; batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i]; } } for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { if (pipesummary[i] != 0) break; } cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG); cnt += sprintf(&page[cnt], "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d " "rtmbe: %d nt: %ld", rcu_torture_current, rcu_torture_current_version, list_empty(&rcu_torture_freelist), atomic_read(&n_rcu_torture_alloc), atomic_read(&n_rcu_torture_alloc_fail), atomic_read(&n_rcu_torture_free), atomic_read(&n_rcu_torture_mberror), n_rcu_torture_timers); if (atomic_read(&n_rcu_torture_mberror) != 0) cnt += sprintf(&page[cnt], " !!!"); cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); if (i > 1) { cnt += sprintf(&page[cnt], "!!! "); atomic_inc(&n_rcu_torture_error); WARN_ON_ONCE(1); } cnt += sprintf(&page[cnt], "Reader Pipe: "); for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) cnt += sprintf(&page[cnt], " %ld", pipesummary[i]); cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); cnt += sprintf(&page[cnt], "Reader Batch: "); for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) cnt += sprintf(&page[cnt], " %ld", batchsummary[i]); cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); cnt += sprintf(&page[cnt], "Free-Block Circulation: "); for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { cnt += sprintf(&page[cnt], " %d", atomic_read(&rcu_torture_wcount[i])); } cnt += sprintf(&page[cnt], "\n"); if (cur_ops->stats) cnt += cur_ops->stats(&page[cnt]); return cnt; }
/* * Print torture statistics. Caller must ensure that there is only * one call to this function at a given time!!! This is normally * accomplished by relying on the module system to only have one copy * of the module loaded, and then by giving the rcu_torture_stats * kthread full control (or the init/cleanup functions when rcu_torture_stats * thread is not running). */ static void rcu_torture_stats_print(void) { int cnt;
cnt = rcu_torture_printk(printk_buf); printk(KERN_ALERT "%s", printk_buf); }
/* * Periodically prints torture statistics, if periodic statistics printing * was specified via the stat_interval module parameter. * * No need to worry about fullstop here, since this one doesn't reference * volatile state or register callbacks. */ static int rcu_torture_stats(void *arg) { VERBOSE_PRINTK_STRING("rcu_torture_stats task started"); do { schedule_timeout_interruptible(stat_interval * HZ); rcu_torture_stats_print(); } while (!kthread_should_stop()); VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping"); return 0; }
static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs. */ static void rcu_torture_shuffle_tasks(void) { cpumask_t tmp_mask; int i;
cpus_setall(tmp_mask); get_online_cpus();
/* No point in shuffling if there is only one online CPU (ex: UP) */ if (num_online_cpus() == 1) { put_online_cpus(); return; }
if (rcu_idle_cpu != -1) cpu_clear(rcu_idle_cpu, tmp_mask);
set_cpus_allowed_ptr(current, &tmp_mask);
if (reader_tasks) { for (i = 0; i < nrealreaders; i++) if (reader_tasks[i]) set_cpus_allowed_ptr(reader_tasks[i], &tmp_mask); }
if (fakewriter_tasks) { for (i = 0; i < nfakewriters; i++) if (fakewriter_tasks[i]) set_cpus_allowed_ptr(fakewriter_tasks[i], &tmp_mask); }
if (writer_task) set_cpus_allowed_ptr(writer_task, &tmp_mask);
if (stats_task) set_cpus_allowed_ptr(stats_task, &tmp_mask);
if (rcu_idle_cpu == -1) rcu_idle_cpu = num_online_cpus() - 1; else rcu_idle_cpu--;
put_online_cpus(); }
/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the * system to become idle at a time and cut off its timer ticks. This is meant * to test the support for such tickless idle CPU in RCU. */ static int rcu_torture_shuffle(void *arg) { VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started"); do { schedule_timeout_interruptible(shuffle_interval * HZ); rcu_torture_shuffle_tasks(); } while (!kthread_should_stop()); VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping"); return 0; }
/* Cause the rcutorture test to "stutter", starting and stopping all * threads periodically. */ static int rcu_torture_stutter(void *arg) { VERBOSE_PRINTK_STRING("rcu_torture_stutter task started"); do { schedule_timeout_interruptible(stutter * HZ); stutter_pause_test = 1; if (!kthread_should_stop()) schedule_timeout_interruptible(stutter * HZ); stutter_pause_test = 0; } while (!kthread_should_stop()); VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping"); return 0; }
static inline void rcu_torture_print_module_parms(char *tag) { printk(KERN_ALERT "%s" TORTURE_FLAG "--- %s: nreaders=%d nfakewriters=%d " "stat_interval=%d verbose=%d test_no_idle_hz=%d " "shuffle_interval=%d stutter=%d irqreader=%d\n", torture_type, tag, nrealreaders, nfakewriters, stat_interval, verbose, test_no_idle_hz, shuffle_interval, stutter, irqreader); }
static void rcu_torture_cleanup(void) { int i;
fullstop = 1; if (stutter_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task"); kthread_stop(stutter_task); } stutter_task = NULL; if (shuffler_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task"); kthread_stop(shuffler_task); } shuffler_task = NULL;
if (writer_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task"); kthread_stop(writer_task); } writer_task = NULL;
if (reader_tasks) { for (i = 0; i < nrealreaders; i++) { if (reader_tasks[i]) { VERBOSE_PRINTK_STRING( "Stopping rcu_torture_reader task"); kthread_stop(reader_tasks[i]); } reader_tasks[i] = NULL; } kfree(reader_tasks); reader_tasks = NULL; } rcu_torture_current = NULL;
if (fakewriter_tasks) { for (i = 0; i < nfakewriters; i++) { if (fakewriter_tasks[i]) { VERBOSE_PRINTK_STRING( "Stopping rcu_torture_fakewriter task"); kthread_stop(fakewriter_tasks[i]); } fakewriter_tasks[i] = NULL; } kfree(fakewriter_tasks); fakewriter_tasks = NULL; }
if (stats_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task"); kthread_stop(stats_task); } stats_task = NULL;
/* Wait for all RCU callbacks to fire. */
if (cur_ops->cb_barrier != NULL) cur_ops->cb_barrier();
rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
if (cur_ops->cleanup) cur_ops->cleanup(); if (atomic_read(&n_rcu_torture_error)) rcu_torture_print_module_parms("End of test: FAILURE"); else rcu_torture_print_module_parms("End of test: SUCCESS"); }
static int __init rcu_torture_init(void) { int i; int cpu; int firsterr = 0; static struct rcu_torture_ops *torture_ops[] = { &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops, &srcu_ops, &sched_ops, &sched_ops_sync, };
/* Process args and tell the world that the torturer is on the job. */ for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { cur_ops = torture_ops[i]; if (strcmp(torture_type, cur_ops->name) == 0) break; } if (i == ARRAY_SIZE(torture_ops)) { printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n", torture_type); return (-EINVAL); } if (cur_ops->init) cur_ops->init(); /* no "goto unwind" prior to this point!!! */
if (nreaders >= 0) nrealreaders = nreaders; else nrealreaders = 2 * num_online_cpus(); rcu_torture_print_module_parms("Start of test"); fullstop = 0;
/* Set up the freelist. */
INIT_LIST_HEAD(&rcu_torture_freelist); for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { rcu_tortures[i].rtort_mbtest = 0; list_add_tail(&rcu_tortures[i].rtort_free, &rcu_torture_freelist); }
/* Initialize the statistics so that each run gets its own numbers. */
rcu_torture_current = NULL; rcu_torture_current_version = 0; atomic_set(&n_rcu_torture_alloc, 0); atomic_set(&n_rcu_torture_alloc_fail, 0); atomic_set(&n_rcu_torture_free, 0); atomic_set(&n_rcu_torture_mberror, 0); atomic_set(&n_rcu_torture_error, 0); for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) atomic_set(&rcu_torture_wcount[i], 0); for_each_possible_cpu(cpu) { for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { per_cpu(rcu_torture_count, cpu)[i] = 0; per_cpu(rcu_torture_batch, cpu)[i] = 0; } }
/* Start up the kthreads. */
VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task"); writer_task = kthread_run(rcu_torture_writer, NULL, "rcu_torture_writer"); if (IS_ERR(writer_task)) { firsterr = PTR_ERR(writer_task); VERBOSE_PRINTK_ERRSTRING("Failed to create writer"); writer_task = NULL; goto unwind; } fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]), GFP_KERNEL); if (fakewriter_tasks == NULL) { VERBOSE_PRINTK_ERRSTRING("out of memory"); firsterr = -ENOMEM; goto unwind; } for (i = 0; i < nfakewriters; i++) { VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task"); fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL, "rcu_torture_fakewriter"); if (IS_ERR(fakewriter_tasks[i])) { firsterr = PTR_ERR(fakewriter_tasks[i]); VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter"); fakewriter_tasks[i] = NULL; goto unwind; } } reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]), GFP_KERNEL); if (reader_tasks == NULL) { VERBOSE_PRINTK_ERRSTRING("out of memory"); firsterr = -ENOMEM; goto unwind; } for (i = 0; i < nrealreaders; i++) { VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task"); reader_tasks[i] = kthread_run(rcu_torture_reader, NULL, "rcu_torture_reader"); if (IS_ERR(reader_tasks[i])) { firsterr = PTR_ERR(reader_tasks[i]); VERBOSE_PRINTK_ERRSTRING("Failed to create reader"); reader_tasks[i] = NULL; goto unwind; } } if (stat_interval > 0) { VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task"); stats_task = kthread_run(rcu_torture_stats, NULL, "rcu_torture_stats"); if (IS_ERR(stats_task)) { firsterr = PTR_ERR(stats_task); VERBOSE_PRINTK_ERRSTRING("Failed to create stats"); stats_task = NULL; goto unwind; } } if (test_no_idle_hz) { rcu_idle_cpu = num_online_cpus() - 1; /* Create the shuffler thread */ shuffler_task = kthread_run(rcu_torture_shuffle, NULL, "rcu_torture_shuffle"); if (IS_ERR(shuffler_task)) { firsterr = PTR_ERR(shuffler_task); VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler"); shuffler_task = NULL; goto unwind; } } if (stutter < 0) stutter = 0; if (stutter) { /* Create the stutter thread */ stutter_task = kthread_run(rcu_torture_stutter, NULL, "rcu_torture_stutter"); if (IS_ERR(stutter_task)) { firsterr = PTR_ERR(stutter_task); VERBOSE_PRINTK_ERRSTRING("Failed to create stutter"); stutter_task = NULL; goto unwind; } } return 0;
unwind: rcu_torture_cleanup(); return firsterr; }
module_init(rcu_torture_init); module_exit(rcu_torture_cleanup);
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