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x86/dumpstack: Introduce die_addr() for die() with #GP fault address

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Split __die() into __die_header() and __die_body(). This allows inserting
extra information below the header line that initiates the bug report.

Introduce a new function die_addr() that behaves like die(), but is for
faults only and uses __die_header() and __die_body() so that a future
commit can print extra information after the header line.

 [ bp: Comment the KASAN-specific usage of gp_addr. ]

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kasan-dev@googlegroups.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191218231150.12139-3-jannh@google.com
This commit is contained in:
Jann Horn 2019-12-19 00:11:49 +01:00 committed by Borislav Petkov
parent 59c1dcbed5
commit aa49f20462
3 changed files with 32 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/kdebug.h
View File

@ -33,6 +33,7 @@ enum show_regs_mode {
};
extern void die(const char *, struct pt_regs *,long);
void die_addr(const char *str, struct pt_regs *regs, long err, long gp_addr);
extern int __must_check __die(const char *, struct pt_regs *, long);
extern void show_stack_regs(struct pt_regs *regs);
extern void __show_regs(struct pt_regs *regs, enum show_regs_mode);

24
arch/x86/kernel/dumpstack.c
View File

@ -365,7 +365,7 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
}
NOKPROBE_SYMBOL(oops_end);
int __die(const char *str, struct pt_regs *regs, long err)
static void __die_header(const char *str, struct pt_regs *regs, long err)
{
const char *pr = "";
@ -384,7 +384,11 @@ int __die(const char *str, struct pt_regs *regs, long err)
IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "",
IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ?
(boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : "");
}
NOKPROBE_SYMBOL(__die_header);
static int __die_body(const char *str, struct pt_regs *regs, long err)
{
show_regs(regs);
print_modules();
@ -394,6 +398,13 @@ int __die(const char *str, struct pt_regs *regs, long err)
return 0;
}
NOKPROBE_SYMBOL(__die_body);
int __die(const char *str, struct pt_regs *regs, long err)
{
__die_header(str, regs, err);
return __die_body(str, regs, err);
}
NOKPROBE_SYMBOL(__die);
/*
@ -410,6 +421,17 @@ void die(const char *str, struct pt_regs *regs, long err)
oops_end(flags, regs, sig);
}
void die_addr(const char *str, struct pt_regs *regs, long err, long gp_addr)
{
unsigned long flags = oops_begin();
int sig = SIGSEGV;
__die_header(str, regs, err);
if (__die_body(str, regs, err))
sig = 0;
oops_end(flags, regs, sig);
}
void show_regs(struct pt_regs *regs)
{
show_regs_print_info(KERN_DEFAULT);

9
arch/x86/kernel/traps.c
View File

@ -619,7 +619,14 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code)
"maybe for address",
gp_addr);
die(desc, regs, error_code);
/*
* KASAN is interested only in the non-canonical case, clear it
* otherwise.
*/
if (hint != GP_NON_CANONICAL)
gp_addr = 0;
die_addr(desc, regs, error_code, gp_addr);
return;
}