| Message ID | 20231015202650.85777-1-pedro.falcato@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: kmsan: Panic on failure to allocate early boot metadata | expand |
On Sun, Oct 15, 2023 at 9:26 PM Pedro Falcato <pedro.falcato@gmail.com> wrote: > > Given large enough allocations and a machine with low enough memory (i.e > a default QEMU VM), it's entirely possible that > kmsan_init_alloc_meta_for_range's shadow+origin allocation fails. Ugh, forgot to run checkpatch.pl until it was too late :/ > Instead of eating a NULL deref kernel oops, check explicitly for memblock_alloc() If there's no need for a v2, please wrap the above line and... > failure and panic with a nice error message. > > Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com> > --- > mm/kmsan/shadow.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c > index 87318f9170f..3dae3d9c0b3 100644 > --- a/mm/kmsan/shadow.c > +++ b/mm/kmsan/shadow.c > @@ -285,12 +285,18 @@ void __init kmsan_init_alloc_meta_for_range(void *start, void *end) > size = PAGE_ALIGN((u64)end - (u64)start); > shadow = memblock_alloc(size, PAGE_SIZE); > origin = memblock_alloc(size, PAGE_SIZE); > + > + if (!shadow || !origin) > + panic("%s: Failed to allocate metadata memory for early boot range " > + "of size %llu", unwrap this string like this: "%s: Failed to allocate metadata memory for early boot range of size %llu", Silly mistake...
On Sun, 15 Oct 2023 at 22:35, Pedro Falcato <pedro.falcato@gmail.com> wrote: > > On Sun, Oct 15, 2023 at 9:26 PM Pedro Falcato <pedro.falcato@gmail.com> wrote: > > > > Given large enough allocations and a machine with low enough memory (i.e > > a default QEMU VM), it's entirely possible that > > kmsan_init_alloc_meta_for_range's shadow+origin allocation fails. > > Ugh, forgot to run checkpatch.pl until it was too late :/ > > > Instead of eating a NULL deref kernel oops, check explicitly for memblock_alloc() > > If there's no need for a v2, please wrap the above line and... Probably easier to send v2. Otherwise looks good. > > failure and panic with a nice error message. > > > > Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com> > > --- > > mm/kmsan/shadow.c | 10 ++++++++-- > > 1 file changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c > > index 87318f9170f..3dae3d9c0b3 100644 > > --- a/mm/kmsan/shadow.c > > +++ b/mm/kmsan/shadow.c > > @@ -285,12 +285,18 @@ void __init kmsan_init_alloc_meta_for_range(void *start, void *end) > > size = PAGE_ALIGN((u64)end - (u64)start); > > shadow = memblock_alloc(size, PAGE_SIZE); > > origin = memblock_alloc(size, PAGE_SIZE); > > + > > + if (!shadow || !origin) > > + panic("%s: Failed to allocate metadata memory for early boot range " > > + "of size %llu", > > unwrap this string like this: > "%s: Failed to allocate metadata memory for early boot range of size %llu", > > Silly mistake... > > -- > Pedro
diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c index 87318f9170f..3dae3d9c0b3 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -285,12 +285,18 @@ void __init kmsan_init_alloc_meta_for_range(void *start, void *end) size = PAGE_ALIGN((u64)end - (u64)start); shadow = memblock_alloc(size, PAGE_SIZE); origin = memblock_alloc(size, PAGE_SIZE); + + if (!shadow || !origin) + panic("%s: Failed to allocate metadata memory for early boot range " + "of size %llu", + __func__, size); + for (u64 addr = 0; addr < size; addr += PAGE_SIZE) { page = virt_to_page_or_null((char *)start + addr); - shadow_p = virt_to_page_or_null((char *)shadow + addr); + shadow_p = virt_to_page((char *)shadow + addr); set_no_shadow_origin_page(shadow_p); shadow_page_for(page) = shadow_p; - origin_p = virt_to_page_or_null((char *)origin + addr); + origin_p = virt_to_page((char *)origin + addr); set_no_shadow_origin_page(origin_p); origin_page_for(page) = origin_p; }
Given large enough allocations and a machine with low enough memory (i.e a default QEMU VM), it's entirely possible that kmsan_init_alloc_meta_for_range's shadow+origin allocation fails. Instead of eating a NULL deref kernel oops, check explicitly for memblock_alloc() failure and panic with a nice error message. Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com> --- mm/kmsan/shadow.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)