On Tue, Jun 11, 2024 at 12:46 PM Tao Liu <l...@redhat.com> wrote:
> Hi Lianbo,
>
> The patch looks good to me, tested OK, so ack.
>
>
Applied:
https://github.com/crash-utility/crash/commit/6752571d8d782d07537a258a1ec8919ebd1308ad
Thanks
Lianbo
> Thanks,
> Tao Liu
>
> On Wed, Jun 5, 2024 at 6:05 PM Lianbo Jiang <liji...@redhat.com> wrote:
> >
> > Kernel commit 223b5e57d0d5 ("mm/execmem, arch: convert remaining
> > overrides of module_alloc to execmem") makes crash session loading
> > failure as below:
> >
> > # ./crash -s
> > crash: seek error: kernel virtual address: ffffffff826bb418 type:
> "page_offset_base"
> >
> > For X86 64 architecture, currently crash will search for symbol
> > "module_load_offset" to determine if the KASLR is enabled, and go
> > into the relevant code block. But the symbols "module_load_offset"
> > has been removed since Linux v6.10-rc1, which caused the current
> > failure.
> >
> > And this issue can occur with live debugging and core dump file
> > debugging.
> >
> > Let's check the symbol "kaslr_regions" instead of "module_load_offset"
> > to fix it.
> >
> > Signed-off-by: Lianbo Jiang <liji...@redhat.com>
> > ---
> > symbols.c | 13 ++++++++-----
> > 1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > diff --git a/symbols.c b/symbols.c
> > index b7627a83587a..1cdf21d86d69 100644
> > --- a/symbols.c
> > +++ b/symbols.c
> > @@ -619,9 +619,9 @@ strip_symbol_end(const char *name, char *buf)
> > * or in /proc/kallsyms on a live system.
> > *
> > * Setting KASLR_CHECK will trigger a search for "module_load_offset"
> > - * during the initial symbol sort operation, and if found, will
> > - * set (RELOC_AUTO|KASLR). On live systems, the search is done
> > - * here by checking /proc/kallsyms.
> > + * or "kaslr_regions" during the initial symbol sort operation, and
> > + * if found, will set (RELOC_AUTO|KASLR). On live systems, the search
> > + * is done here by checking /proc/kallsyms.
> > */
> > static void
> > kaslr_init(void)
> > @@ -646,7 +646,8 @@ kaslr_init(void)
> > st->_stext_vmlinux = UNINITIALIZED;
> >
> > if (ACTIVE() && /* Linux 3.15 */
> > - (symbol_value_from_proc_kallsyms("module_load_offset") !=
> BADVAL)) {
> > + ((symbol_value_from_proc_kallsyms("kaslr_regions") !=
> BADVAL) ||
> > + (symbol_value_from_proc_kallsyms("module_load_offset") !=
> BADVAL))) {
> > kt->flags2 |= (RELOC_AUTO|KASLR);
> > st->_stext_vmlinux = UNINITIALIZED;
> > }
> > @@ -14247,7 +14248,9 @@ numeric_forward(const void *P_x, const void *P_y)
> > st->_stext_vmlinux = valueof(y);
> > }
> > if (kt->flags2 & KASLR_CHECK) {
> > - if (STREQ(x->name, "module_load_offset") ||
> > + if (STREQ(x->name, "kaslr_regions") ||
> > + STREQ(y->name, "kaslr_regions") ||
> > + STREQ(x->name, "module_load_offset") ||
> > STREQ(y->name, "module_load_offset")) {
> > kt->flags2 &= ~KASLR_CHECK;
> > kt->flags2 |= (RELOC_AUTO|KASLR);
> > --
> > 2.45.1
> > --
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>
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