A set of unwinder and tooling fixes:

- Ensure that the stack pointer on x86 is aligned again so that the
     unwinder does not read past the end of the stack
 
   - Discard .note.gnu.property section which has a pointlessly different
     alignment than the other note sections. That confuses tooling of all
     sorts including readelf, libbpf and pahole.
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Merge tag 'objtool-urgent-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull unwinder fixes from Thomas Gleixner:
 "A set of unwinder and tooling fixes:

   - Ensure that the stack pointer on x86 is aligned again so that the
     unwinder does not read past the end of the stack

   - Discard .note.gnu.property section which has a pointlessly
     different alignment than the other note sections. That confuses
     tooling of all sorts including readelf, libbpf and pahole"

* tag 'objtool-urgent-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/show_trace_log_lvl: Ensure stack pointer is aligned, again
  vmlinux.lds.h: Discard .note.gnu.property section
This commit is contained in:
Linus Torvalds 2023-05-28 07:33:29 -04:00
commit abbf7fa15b
2 changed files with 13 additions and 3 deletions

View File

@ -195,7 +195,6 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
printk("%sCall Trace:\n", log_lvl);
unwind_start(&state, task, regs, stack);
stack = stack ? : get_stack_pointer(task, regs);
regs = unwind_get_entry_regs(&state, &partial);
/*
@ -214,9 +213,13 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
* - hardirq stack
* - entry stack
*/
for ( ; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
for (stack = stack ?: get_stack_pointer(task, regs);
stack;
stack = stack_info.next_sp) {
const char *stack_name;
stack = PTR_ALIGN(stack, sizeof(long));
if (get_stack_info(stack, task, &stack_info, &visit_mask)) {
/*
* We weren't on a valid stack. It's possible that

View File

@ -891,9 +891,16 @@
/*
* Discard .note.GNU-stack, which is emitted as PROGBITS by the compiler.
* Otherwise, the type of .notes section would become PROGBITS instead of NOTES.
*
* Also, discard .note.gnu.property, otherwise it forces the notes section to
* be 8-byte aligned which causes alignment mismatches with the kernel's custom
* 4-byte aligned notes.
*/
#define NOTES \
/DISCARD/ : { *(.note.GNU-stack) } \
/DISCARD/ : { \
*(.note.GNU-stack) \
*(.note.gnu.property) \
} \
.notes : AT(ADDR(.notes) - LOAD_OFFSET) { \
BOUNDED_SECTION_BY(.note.*, _notes) \
} NOTES_HEADERS \