Revision 74545f63890e38520eb4d1dbedcadaa9c0dbc824 authored by David Carrillo-Cisneros on 23 December 2016, 01:17:40 UTC, committed by Ingo Molnar on 05 January 2017, 08:13:55 UTC
The conversion of Intel PMU drivers into modules did not include reference counting. The machine will crash when attempting to access deleted code if an event from a module PMU is started and the module removed before the event is destroyed. i.e. this crashes the machine: $ insmod intel-rapl-perf.ko $ perf stat -e power/energy-cores/ -C 0 & $ rmmod intel-rapl-perf.ko Set THIS_MODULE to pmu->module in Intel module PMUs so that generic code can handle reference counting and deny rmmod while an event still exists. Signed-off-by: David Carrillo-Cisneros <davidcc@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1482455860-116269-1-git-send-email-davidcc@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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binfmt_em86.c
/*
* linux/fs/binfmt_em86.c
*
* Based on linux/fs/binfmt_script.c
* Copyright (C) 1996 Martin von Löwis
* original #!-checking implemented by tytso.
*
* em86 changes Copyright (C) 1997 Jim Paradis
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/errno.h>
#define EM86_INTERP "/usr/bin/em86"
#define EM86_I_NAME "em86"
static int load_em86(struct linux_binprm *bprm)
{
const char *i_name, *i_arg;
char *interp;
struct file * file;
int retval;
struct elfhdr elf_ex;
/* Make sure this is a Linux/Intel ELF executable... */
elf_ex = *((struct elfhdr *)bprm->buf);
if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
return -ENOEXEC;
/* First of all, some simple consistency checks */
if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
(!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) ||
!bprm->file->f_op->mmap) {
return -ENOEXEC;
}
/* Need to be able to load the file after exec */
if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
return -ENOENT;
allow_write_access(bprm->file);
fput(bprm->file);
bprm->file = NULL;
/* Unlike in the script case, we don't have to do any hairy
* parsing to find our interpreter... it's hardcoded!
*/
interp = EM86_INTERP;
i_name = EM86_I_NAME;
i_arg = NULL; /* We reserve the right to add an arg later */
/*
* Splice in (1) the interpreter's name for argv[0]
* (2) (optional) argument to interpreter
* (3) filename of emulated file (replace argv[0])
*
* This is done in reverse order, because of how the
* user environment and arguments are stored.
*/
remove_arg_zero(bprm);
retval = copy_strings_kernel(1, &bprm->filename, bprm);
if (retval < 0) return retval;
bprm->argc++;
if (i_arg) {
retval = copy_strings_kernel(1, &i_arg, bprm);
if (retval < 0) return retval;
bprm->argc++;
}
retval = copy_strings_kernel(1, &i_name, bprm);
if (retval < 0) return retval;
bprm->argc++;
/*
* OK, now restart the process with the interpreter's inode.
* Note that we use open_exec() as the name is now in kernel
* space, and we don't need to copy it.
*/
file = open_exec(interp);
if (IS_ERR(file))
return PTR_ERR(file);
bprm->file = file;
retval = prepare_binprm(bprm);
if (retval < 0)
return retval;
return search_binary_handler(bprm);
}
static struct linux_binfmt em86_format = {
.module = THIS_MODULE,
.load_binary = load_em86,
};
static int __init init_em86_binfmt(void)
{
register_binfmt(&em86_format);
return 0;
}
static void __exit exit_em86_binfmt(void)
{
unregister_binfmt(&em86_format);
}
core_initcall(init_em86_binfmt);
module_exit(exit_em86_binfmt);
MODULE_LICENSE("GPL");
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