Revision 3cb5f1a3e58c0bd70d47d9907cc5c65192281dee authored by Steven Rostedt on 23 December 2010, 19:46:06 UTC, committed by Benjamin Herrenschmidt on 21 January 2011, 03:08:33 UTC
When an interrupt occurs in userspace, we can call trace_hardirqs_on/off() With one level stack. But if we have irqsoff tracing enabled, it checks both CALLER_ADDR0 and CALLER_ADDR1. The second call goes two stack frames up. If this is from user space, then there may not exist a second stack. Add a second stack when calling trace_hardirqs_on/off() otherwise the following oops might occur: Oops: Kernel access of bad area, sig: 11 [#1] PREEMPT SMP NR_CPUS=2 PA Semi PWRficient last sysfs file: /sys/block/sda/size Modules linked in: ohci_hcd ehci_hcd usbcore NIP: c0000000000e1c00 LR: c0000000000034d4 CTR: 000000011012c440 REGS: c00000003e2f3af0 TRAP: 0300 Not tainted (2.6.37-rc6+) MSR: 9000000000001032 <ME,IR,DR> CR: 48044444 XER: 20000000 DAR: 00000001ffb9db50, DSISR: 0000000040000000 TASK = c00000003e1a00a0[2088] 'emacs' THREAD: c00000003e2f0000 CPU: 1 GPR00: 0000000000000001 c00000003e2f3d70 c00000000084e0d0 c0000000008816e8 GPR04: 000000001034c678 000000001032e8f9 0000000010336540 0000000040020000 GPR08: 0000000040020000 00000001ffb9db40 c00000003e2f3e30 0000000060000000 GPR12: 100000000000f032 c00000000fff0280 000000001032e8c9 0000000000000008 GPR16: 00000000105be9c0 00000000105be950 00000000105be9b0 00000000105be950 GPR20: 00000000ffb9dc50 00000000ffb9dbf0 00000000102f0000 00000000102f0000 GPR24: 00000000102e0000 00000000102f0000 0000000010336540 c0000000009ded38 GPR28: 00000000102e0000 c0000000000034d4 c0000000007ccb10 c00000003e2f3d70 NIP [c0000000000e1c00] .trace_hardirqs_off+0xb0/0x1d0 LR [c0000000000034d4] decrementer_common+0xd4/0x100 Call Trace: [c00000003e2f3d70] [c00000003e2f3e30] 0xc00000003e2f3e30 (unreliable) [c00000003e2f3e30] [c0000000000034d4] decrementer_common+0xd4/0x100 Instruction dump: 81690000 7f8b0000 419e0018 f84a0028 60000000 60000000 60000000 e95f0000 80030000 e92a0000 eb6301f8 2f800000 <eb890010> 41fe00dc a06d000a eb1e8050 ---[ end trace 4ec7fd2be9240928 ]--- Reported-by: Joerg Sommer <joerg@alea.gnuu.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
1 parent c033728
util.h
/*
* linux/ipc/util.h
* Copyright (C) 1999 Christoph Rohland
*
* ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
* namespaces support. 2006 OpenVZ, SWsoft Inc.
* Pavel Emelianov <xemul@openvz.org>
*/
#ifndef _IPC_UTIL_H
#define _IPC_UTIL_H
#include <linux/unistd.h>
#include <linux/err.h>
#define SEQ_MULTIPLIER (IPCMNI)
void sem_init (void);
void msg_init (void);
void shm_init (void);
struct ipc_namespace;
#ifdef CONFIG_POSIX_MQUEUE
extern void mq_clear_sbinfo(struct ipc_namespace *ns);
extern void mq_put_mnt(struct ipc_namespace *ns);
#else
static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
static inline void mq_put_mnt(struct ipc_namespace *ns) { }
#endif
#ifdef CONFIG_SYSVIPC
void sem_init_ns(struct ipc_namespace *ns);
void msg_init_ns(struct ipc_namespace *ns);
void shm_init_ns(struct ipc_namespace *ns);
void sem_exit_ns(struct ipc_namespace *ns);
void msg_exit_ns(struct ipc_namespace *ns);
void shm_exit_ns(struct ipc_namespace *ns);
#else
static inline void sem_init_ns(struct ipc_namespace *ns) { }
static inline void msg_init_ns(struct ipc_namespace *ns) { }
static inline void shm_init_ns(struct ipc_namespace *ns) { }
static inline void sem_exit_ns(struct ipc_namespace *ns) { }
static inline void msg_exit_ns(struct ipc_namespace *ns) { }
static inline void shm_exit_ns(struct ipc_namespace *ns) { }
#endif
/*
* Structure that holds the parameters needed by the ipc operations
* (see after)
*/
struct ipc_params {
key_t key;
int flg;
union {
size_t size; /* for shared memories */
int nsems; /* for semaphores */
} u; /* holds the getnew() specific param */
};
/*
* Structure that holds some ipc operations. This structure is used to unify
* the calls to sys_msgget(), sys_semget(), sys_shmget()
* . routine to call to create a new ipc object. Can be one of newque,
* newary, newseg
* . routine to call to check permissions for a new ipc object.
* Can be one of security_msg_associate, security_sem_associate,
* security_shm_associate
* . routine to call for an extra check if needed
*/
struct ipc_ops {
int (*getnew) (struct ipc_namespace *, struct ipc_params *);
int (*associate) (struct kern_ipc_perm *, int);
int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
};
struct seq_file;
struct ipc_ids;
void ipc_init_ids(struct ipc_ids *);
#ifdef CONFIG_PROC_FS
void __init ipc_init_proc_interface(const char *path, const char *header,
int ids, int (*show)(struct seq_file *, void *));
#else
#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
#endif
#define IPC_SEM_IDS 0
#define IPC_MSG_IDS 1
#define IPC_SHM_IDS 2
#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
/* must be called with ids->rw_mutex acquired for writing */
int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
/* must be called with ids->rw_mutex acquired for reading */
int ipc_get_maxid(struct ipc_ids *);
/* must be called with both locks acquired. */
void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
/* must be called with ipcp locked */
int ipcperms(struct kern_ipc_perm *ipcp, short flg);
/* for rare, potentially huge allocations.
* both function can sleep
*/
void* ipc_alloc(int size);
void ipc_free(void* ptr, int size);
/*
* For allocation that need to be freed by RCU.
* Objects are reference counted, they start with reference count 1.
* getref increases the refcount, the putref call that reduces the recount
* to 0 schedules the rcu destruction. Caller must guarantee locking.
*/
void* ipc_rcu_alloc(int size);
void ipc_rcu_getref(void *ptr);
void ipc_rcu_putref(void *ptr);
struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
struct ipc64_perm *perm, int extra_perm);
#ifndef __ARCH_WANT_IPC_PARSE_VERSION
/* On IA-64, we always use the "64-bit version" of the IPC structures. */
# define ipc_parse_version(cmd) IPC_64
#else
int ipc_parse_version (int *cmd);
#endif
extern void free_msg(struct msg_msg *msg);
extern struct msg_msg *load_msg(const void __user *src, int len);
extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
extern void recompute_msgmni(struct ipc_namespace *);
static inline int ipc_buildid(int id, int seq)
{
return SEQ_MULTIPLIER * seq + id;
}
/*
* Must be called with ipcp locked
*/
static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
{
if (uid / SEQ_MULTIPLIER != ipcp->seq)
return 1;
return 0;
}
static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
{
rcu_read_lock();
spin_lock(&perm->lock);
}
static inline void ipc_unlock(struct kern_ipc_perm *perm)
{
spin_unlock(&perm->lock);
rcu_read_unlock();
}
struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
struct ipc_ops *ops, struct ipc_params *params);
void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
#endif
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