https://github.com/torvalds/linux
Revision 7dec80ccbe310fb7e225bf21c48c672bb780ce7b authored by Josh Poimboeuf on 18 May 2018, 20:10:34 UTC, committed by Ingo Molnar on 19 May 2018, 06:10:04 UTC
With the following commit: fd35c88b7417 ("objtool: Support GCC 8 switch tables") I added a "can't find switch jump table" warning, to stop covering up silent failures if add_switch_table() can't find anything. That warning found yet another bug in the objtool switch table detection logic. For cases 1 and 2 (as described in the comments of find_switch_table()), the find_symbol_containing() check doesn't adjust the offset for RIP-relative switch jumps. Incidentally, this bug was already fixed for case 3 with: 6f5ec2993b1f ("objtool: Detect RIP-relative switch table references") However, that commit missed the fix for cases 1 and 2. The different cases are now starting to look more and more alike. So fix the bug by consolidating them into a single case, by checking the original dynamic jump instruction in the case 3 loop. This also simplifies the code and makes it more robust against future switch table detection issues -- of which I'm sure there will be many... Switch table detection has been the most fragile area of objtool, by far. I long for the day when we'll have a GCC plugin for annotating switch tables. Linus asked me to delay such a plugin due to the flakiness of the plugin infrastructure in older versions of GCC, so this rickety code is what we're stuck with for now. At least the code is now a little simpler than it was. Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/f400541613d45689086329432f3095119ffbc328.1526674218.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent 6f5ec29
Tip revision: 7dec80ccbe310fb7e225bf21c48c672bb780ce7b authored by Josh Poimboeuf on 18 May 2018, 20:10:34 UTC
objtool: Detect RIP-relative switch table references, part 2
objtool: Detect RIP-relative switch table references, part 2
Tip revision: 7dec80c
internal.h
/* General netfs cache on cache files internal defs
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) "CacheFiles: " fmt
#include <linux/fscache-cache.h>
#include <linux/timer.h>
#include <linux/wait_bit.h>
#include <linux/cred.h>
#include <linux/workqueue.h>
#include <linux/security.h>
struct cachefiles_cache;
struct cachefiles_object;
extern unsigned cachefiles_debug;
#define CACHEFILES_DEBUG_KENTER 1
#define CACHEFILES_DEBUG_KLEAVE 2
#define CACHEFILES_DEBUG_KDEBUG 4
#define cachefiles_gfp (__GFP_RECLAIM | __GFP_NORETRY | __GFP_NOMEMALLOC)
/*
* node records
*/
struct cachefiles_object {
struct fscache_object fscache; /* fscache handle */
struct cachefiles_lookup_data *lookup_data; /* cached lookup data */
struct dentry *dentry; /* the file/dir representing this object */
struct dentry *backer; /* backing file */
loff_t i_size; /* object size */
unsigned long flags;
#define CACHEFILES_OBJECT_ACTIVE 0 /* T if marked active */
atomic_t usage; /* object usage count */
uint8_t type; /* object type */
uint8_t new; /* T if object new */
spinlock_t work_lock;
struct rb_node active_node; /* link in active tree (dentry is key) */
};
extern struct kmem_cache *cachefiles_object_jar;
/*
* Cache files cache definition
*/
struct cachefiles_cache {
struct fscache_cache cache; /* FS-Cache record */
struct vfsmount *mnt; /* mountpoint holding the cache */
struct dentry *graveyard; /* directory into which dead objects go */
struct file *cachefilesd; /* manager daemon handle */
const struct cred *cache_cred; /* security override for accessing cache */
struct mutex daemon_mutex; /* command serialisation mutex */
wait_queue_head_t daemon_pollwq; /* poll waitqueue for daemon */
struct rb_root active_nodes; /* active nodes (can't be culled) */
rwlock_t active_lock; /* lock for active_nodes */
atomic_t gravecounter; /* graveyard uniquifier */
atomic_t f_released; /* number of objects released lately */
atomic_long_t b_released; /* number of blocks released lately */
unsigned frun_percent; /* when to stop culling (% files) */
unsigned fcull_percent; /* when to start culling (% files) */
unsigned fstop_percent; /* when to stop allocating (% files) */
unsigned brun_percent; /* when to stop culling (% blocks) */
unsigned bcull_percent; /* when to start culling (% blocks) */
unsigned bstop_percent; /* when to stop allocating (% blocks) */
unsigned bsize; /* cache's block size */
unsigned bshift; /* min(ilog2(PAGE_SIZE / bsize), 0) */
uint64_t frun; /* when to stop culling */
uint64_t fcull; /* when to start culling */
uint64_t fstop; /* when to stop allocating */
sector_t brun; /* when to stop culling */
sector_t bcull; /* when to start culling */
sector_t bstop; /* when to stop allocating */
unsigned long flags;
#define CACHEFILES_READY 0 /* T if cache prepared */
#define CACHEFILES_DEAD 1 /* T if cache dead */
#define CACHEFILES_CULLING 2 /* T if cull engaged */
#define CACHEFILES_STATE_CHANGED 3 /* T if state changed (poll trigger) */
char *rootdirname; /* name of cache root directory */
char *secctx; /* LSM security context */
char *tag; /* cache binding tag */
};
/*
* backing file read tracking
*/
struct cachefiles_one_read {
wait_queue_entry_t monitor; /* link into monitored waitqueue */
struct page *back_page; /* backing file page we're waiting for */
struct page *netfs_page; /* netfs page we're going to fill */
struct fscache_retrieval *op; /* retrieval op covering this */
struct list_head op_link; /* link in op's todo list */
};
/*
* backing file write tracking
*/
struct cachefiles_one_write {
struct page *netfs_page; /* netfs page to copy */
struct cachefiles_object *object;
struct list_head obj_link; /* link in object's lists */
fscache_rw_complete_t end_io_func;
void *context;
};
/*
* auxiliary data xattr buffer
*/
struct cachefiles_xattr {
uint16_t len;
uint8_t type;
uint8_t data[];
};
#include <trace/events/cachefiles.h>
/*
* note change of state for daemon
*/
static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
{
set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
wake_up_all(&cache->daemon_pollwq);
}
/*
* bind.c
*/
extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
/*
* daemon.c
*/
extern const struct file_operations cachefiles_daemon_fops;
extern int cachefiles_has_space(struct cachefiles_cache *cache,
unsigned fnr, unsigned bnr);
/*
* interface.c
*/
extern const struct fscache_cache_ops cachefiles_cache_ops;
/*
* key.c
*/
extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
/*
* namei.c
*/
extern void cachefiles_mark_object_inactive(struct cachefiles_cache *cache,
struct cachefiles_object *object,
blkcnt_t i_blocks);
extern int cachefiles_delete_object(struct cachefiles_cache *cache,
struct cachefiles_object *object);
extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
struct cachefiles_object *object,
const char *key,
struct cachefiles_xattr *auxdata);
extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
struct dentry *dir,
const char *name);
extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
char *filename);
extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
struct dentry *dir, char *filename);
/*
* proc.c
*/
#ifdef CONFIG_CACHEFILES_HISTOGRAM
extern atomic_t cachefiles_lookup_histogram[HZ];
extern atomic_t cachefiles_mkdir_histogram[HZ];
extern atomic_t cachefiles_create_histogram[HZ];
extern int __init cachefiles_proc_init(void);
extern void cachefiles_proc_cleanup(void);
static inline
void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
{
unsigned long jif = jiffies - start_jif;
if (jif >= HZ)
jif = HZ - 1;
atomic_inc(&histogram[jif]);
}
#else
#define cachefiles_proc_init() (0)
#define cachefiles_proc_cleanup() do {} while (0)
#define cachefiles_hist(hist, start_jif) do {} while (0)
#endif
/*
* rdwr.c
*/
extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
struct page *, gfp_t);
extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
struct list_head *, unsigned *,
gfp_t);
extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
gfp_t);
extern int cachefiles_allocate_pages(struct fscache_retrieval *,
struct list_head *, unsigned *, gfp_t);
extern int cachefiles_write_page(struct fscache_storage *, struct page *);
extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
/*
* security.c
*/
extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
struct dentry *root,
const struct cred **_saved_cred);
static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
const struct cred **_saved_cred)
{
*_saved_cred = override_creds(cache->cache_cred);
}
static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
const struct cred *saved_cred)
{
revert_creds(saved_cred);
}
/*
* xattr.c
*/
extern int cachefiles_check_object_type(struct cachefiles_object *object);
extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
struct cachefiles_xattr *auxdata);
extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
struct cachefiles_xattr *auxdata);
extern int cachefiles_check_auxdata(struct cachefiles_object *object);
extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
struct cachefiles_xattr *auxdata);
extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
struct dentry *dentry);
/*
* error handling
*/
#define cachefiles_io_error(___cache, FMT, ...) \
do { \
pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \
fscache_io_error(&(___cache)->cache); \
set_bit(CACHEFILES_DEAD, &(___cache)->flags); \
} while (0)
#define cachefiles_io_error_obj(object, FMT, ...) \
do { \
struct cachefiles_cache *___cache; \
\
___cache = container_of((object)->fscache.cache, \
struct cachefiles_cache, cache); \
cachefiles_io_error(___cache, FMT, ##__VA_ARGS__); \
} while (0)
/*
* debug tracing
*/
#define dbgprintk(FMT, ...) \
printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
#if defined(__KDEBUG)
#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
#elif defined(CONFIG_CACHEFILES_DEBUG)
#define _enter(FMT, ...) \
do { \
if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
kenter(FMT, ##__VA_ARGS__); \
} while (0)
#define _leave(FMT, ...) \
do { \
if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
kleave(FMT, ##__VA_ARGS__); \
} while (0)
#define _debug(FMT, ...) \
do { \
if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
kdebug(FMT, ##__VA_ARGS__); \
} while (0)
#else
#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
#endif
#if 1 /* defined(__KDEBUGALL) */
#define ASSERT(X) \
do { \
if (unlikely(!(X))) { \
pr_err("\n"); \
pr_err("Assertion failed\n"); \
BUG(); \
} \
} while (0)
#define ASSERTCMP(X, OP, Y) \
do { \
if (unlikely(!((X) OP (Y)))) { \
pr_err("\n"); \
pr_err("Assertion failed\n"); \
pr_err("%lx " #OP " %lx is false\n", \
(unsigned long)(X), (unsigned long)(Y)); \
BUG(); \
} \
} while (0)
#define ASSERTIF(C, X) \
do { \
if (unlikely((C) && !(X))) { \
pr_err("\n"); \
pr_err("Assertion failed\n"); \
BUG(); \
} \
} while (0)
#define ASSERTIFCMP(C, X, OP, Y) \
do { \
if (unlikely((C) && !((X) OP (Y)))) { \
pr_err("\n"); \
pr_err("Assertion failed\n"); \
pr_err("%lx " #OP " %lx is false\n", \
(unsigned long)(X), (unsigned long)(Y)); \
BUG(); \
} \
} while (0)
#else
#define ASSERT(X) do {} while (0)
#define ASSERTCMP(X, OP, Y) do {} while (0)
#define ASSERTIF(C, X) do {} while (0)
#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
#endif
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