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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-12-01 21:31:02 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-12-01 21:31:02 -0800 |
| commit | dcd8637edb873bd940e6aa82417dfb33ae980778 (patch) | |
| tree | 6de52669a1e868094ed7e50fd1edfa44e3e7c2cb /arch | |
| parent | e7d81c1ed665e72c55ae5cf2d7601c09842b4013 (diff) | |
| parent | ced37e9ceae50e4cb6cd058963bd315ec9afa651 (diff) | |
Merge tag 'x86-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core x86 updates from Ingo Molnar:
- x86/alternatives: Drop unnecessary test after call to
alt_replace_call() (Juergen Gross)
- x86/dumpstack: Prevent KASAN false positive warnings in
__show_regs() (Tengda Wu)
* tag 'x86-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/dumpstack: Prevent KASAN false positive warnings in __show_regs()
x86/alternative: Drop not needed test after call of alt_replace_call()
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/alternative.c | 9 | ||||
| -rw-r--r-- | arch/x86/kernel/dumpstack.c | 23 |
2 files changed, 24 insertions, 8 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 9f354ebf76e4..e377b06e70e3 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -541,7 +541,7 @@ EXPORT_SYMBOL(BUG_func); * Rewrite the "call BUG_func" replacement to point to the target of the * indirect pv_ops call "call *disp(%ip)". */ -static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a) +static unsigned int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a) { void *target, *bug = &BUG_func; s32 disp; @@ -625,7 +625,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, * order. */ for (a = start; a < end; a++) { - int insn_buff_sz = 0; + unsigned int insn_buff_sz = 0; /* * In case of nested ALTERNATIVE()s the outer alternative might @@ -665,11 +665,8 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, memcpy(insn_buff, replacement, a->replacementlen); insn_buff_sz = a->replacementlen; - if (a->flags & ALT_FLAG_DIRECT_CALL) { + if (a->flags & ALT_FLAG_DIRECT_CALL) insn_buff_sz = alt_replace_call(instr, insn_buff, a); - if (insn_buff_sz < 0) - continue; - } for (; insn_buff_sz < a->instrlen; insn_buff_sz++) insn_buff[insn_buff_sz] = 0x90; diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 71ee20102a8a..b10684dedc58 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -181,8 +181,8 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs, * in false positive reports. Disable instrumentation to avoid those. */ __no_kmsan_checks -static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, - unsigned long *stack, const char *log_lvl) +static void __show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, + unsigned long *stack, const char *log_lvl) { struct unwind_state state; struct stack_info stack_info = {0}; @@ -303,6 +303,25 @@ next: } } +static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, + unsigned long *stack, const char *log_lvl) +{ + /* + * Disable KASAN to avoid false positives during walking another + * task's stacks, as values on these stacks may change concurrently + * with task execution. + */ + bool disable_kasan = task && task != current; + + if (disable_kasan) + kasan_disable_current(); + + __show_trace_log_lvl(task, regs, stack, log_lvl); + + if (disable_kasan) + kasan_enable_current(); +} + void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl) { |