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Fix race between cat /proc/*/wchan and rmmod et al

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kallsyms_lookup() can go iterating over modules list unprotected which is OK
for emergency situations (oops), but not OK for regular stuff like
/proc/*/wchan.

Introduce lookup_symbol_name()/lookup_module_symbol_name() which copy symbol
name into caller-supplied buffer or return -ERANGE.  All copying is done with
module_mutex held, so...

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan
2007-05-08 00:28:43 -07:00
committed by Linus Torvalds
parent ffb4512276
commit 9d65cb4a17
7 changed files with 66 additions and 19 deletions
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7
include/linux/kallsyms.h
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@ -30,6 +30,8 @@ extern int sprint_symbol(char *buffer, unsigned long address);
/* Look up a kernel symbol and print it to the kernel messages. */
extern void __print_symbol(const char *fmt, unsigned long address);
int lookup_symbol_name(unsigned long addr, char *symname);
#else /* !CONFIG_KALLSYMS */
static inline unsigned long kallsyms_lookup_name(const char *name)
@ -58,6 +60,11 @@ static inline int sprint_symbol(char *buffer, unsigned long addr)
return 0;
}
static inline int lookup_symbol_name(unsigned long addr, char *symname)
{
return -ERANGE;
}
/* Stupid that this does nothing, but I didn't create this mess. */
#define __print_symbol(fmt, addr)
#endif /*CONFIG_KALLSYMS*/