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b14b8b1ed0
Since the conversion to generic ptdump we see crashes on 64-bit:
BUG: Unable to handle kernel data access on read at 0xc0eeff7f00000000
Faulting instruction address: 0xc00000000045e5fc
Oops: Kernel access of bad area, sig: 11 [#1]
...
NIP __walk_page_range+0x2bc/0xce0
LR __walk_page_range+0x240/0xce0
Call Trace:
__walk_page_range+0x240/0xce0 (unreliable)
walk_page_range_novma+0x74/0xb0
ptdump_walk_pgd+0x98/0x170
ptdump_check_wx+0x88/0xd0
mark_rodata_ro+0x48/0x80
kernel_init+0x74/0x1a0
ret_from_kernel_thread+0x5c/0x64
What's happening is that have walked off the end of the kernel page
tables, and started dereferencing junk values.
That happens because we initialised the ptdump_range to span all the way
up to 0xffffffffffffffff:
static struct ptdump_range ptdump_range[] __ro_after_init = {
{TASK_SIZE_MAX, ~0UL},
But the kernel page tables don't span that far. So on 64-bit set the end
of the range to be the address immediately past the end of the kernel
page tables, to limit the page table walk to valid addresses.
Fixes:
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|---|---|---|
| .. | ||
| boot | ||
| configs | ||
| crypto | ||
| include | ||
| kernel | ||
| kexec | ||
| kvm | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| perf | ||
| platforms | ||
| purgatory | ||
| sysdev | ||
| tools | ||
| xmon | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile.postlink | ||