archives/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-03-08 04:04:43 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

x86/bug: Handle __WARN_printf() trap in early_fixup_exception()

Browse source 
The commit 5b472b6e5b ("x86_64/bug: Implement __WARN_printf()")
implemented __WARN_printf(), which changed the mechanism to use UD1
instead of UD2. However, it only handles the trap in the runtime IDT
handler, while the early booting IDT handler lacks this handling. As a
result, the usage of WARN() before the runtime IDT setup can lead to
kernel crashes. Since KMSAN is enabled after the runtime IDT setup, it
is safe to use handle_bug() directly in early_fixup_exception() to
address this issue.

Fixes: 5b472b6e5b ("x86_64/bug: Implement __WARN_printf()")
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/c4fb3645f60d3a78629d9870e8fcc8535281c24f.1768016713.git.houwenlong.hwl@antgroup.com
This commit is contained in:
Hou Wenlong 2026-01-10 11:47:37 +08:00 • committed by Peter Zijlstra
parent aa280a08e7
commit a0cb371b52
3 changed files with 5 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/include/asm/traps.h
View file

@ -25,6 +25,8 @@ extern int ibt_selftest_noendbr(void);
void handle_invalid_op(struct pt_regs *regs);
#endif
noinstr bool handle_bug(struct pt_regs *regs);
static inline int get_si_code(unsigned long condition)
{
if (condition & DR_STEP)

2
arch/x86/kernel/traps.c
View file

@ -397,7 +397,7 @@ static inline void handle_invalid_op(struct pt_regs *regs)
ILL_ILLOPN, error_get_trap_addr(regs));
}
static noinstr bool handle_bug(struct pt_regs *regs)
noinstr bool handle_bug(struct pt_regs *regs)
{
unsigned long addr = regs->ip;
bool handled = false;

7
arch/x86/mm/extable.c
View file

@ -411,14 +411,11 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
return;
if (trapnr == X86_TRAP_UD) {
if (report_bug(regs->ip, regs) == BUG_TRAP_TYPE_WARN) {
/* Skip the ud2. */
regs->ip += LEN_UD2;
if (handle_bug(regs))
return;
}
/*
* If this was a BUG and report_bug returns or if this
* If this was a BUG and handle_bug returns or if this
* was just a normal #UD, we want to continue onward and
* crash.
*/