The patch titled
Subject: mm/shmem: Fix race in shmem_undo_range w/THP
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-shmem-fix-race-in-shmem_undo_range-w-thp.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: David Stevens <stevensd(a)chromium.org>
Subject: mm/shmem: Fix race in shmem_undo_range w/THP
Date: Tue, 18 Apr 2023 17:40:31 +0900
Split folios during the second loop of shmem_undo_range. It's not
sufficient to only split folios when dealing with partial pages, since
it's possible for a THP to be faulted in after that point. Calling
truncate_inode_folio in that situation can result in throwing away data
outside of the range being targeted.
Link: https://lkml.kernel.org/r/20230418084031.3439795-1-stevensd@google.com
Fixes: b9a8a4195c7d ("truncate,shmem: Handle truncates that split large folios")
Signed-off-by: David Stevens <stevensd(a)chromium.org>
Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org>
Cc: Suleiman Souhlal <suleiman(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/shmem.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
--- a/mm/shmem.c~mm-shmem-fix-race-in-shmem_undo_range-w-thp
+++ a/mm/shmem.c
@@ -1022,7 +1022,22 @@ whole_folios:
}
VM_BUG_ON_FOLIO(folio_test_writeback(folio),
folio);
- truncate_inode_folio(mapping, folio);
+
+ if (!folio_test_large(folio)) {
+ truncate_inode_folio(mapping, folio);
+ } else if (truncate_inode_partial_folio(folio, lstart, lend)) {
+ /*
+ * If we split a page, reset the loop so that we
+ * pick up the new sub pages. Otherwise the THP
+ * was entirely dropped or the target range was
+ * zeroed, so just continue the loop as is.
+ */
+ if (!folio_test_large(folio)) {
+ folio_unlock(folio);
+ index = start;
+ break;
+ }
+ }
}
folio_unlock(folio);
}
_
Patches currently in -mm which might be from stevensd(a)chromium.org are
mm-shmem-fix-race-in-shmem_undo_range-w-thp.patch
mm-khugepaged-drain-lru-after-swapping-in-shmem.patch
mm-khugepaged-refactor-collapse_file-control-flow.patch
mm-khugepaged-skip-shmem-with-userfaultfd.patch
mm-khugepaged-maintain-page-cache-uptodate-flag.patch
The patch titled
Subject: kasan: hw_tags: avoid invalid virt_to_page()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
kasan-hw_tags-avoid-invalid-virt_to_page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Mark Rutland <mark.rutland(a)arm.com>
Subject: kasan: hw_tags: avoid invalid virt_to_page()
Date: Tue, 18 Apr 2023 17:42:12 +0100
When booting with 'kasan.vmalloc=off', a kernel configured with support
for KASAN_HW_TAGS will explode at boot time due to bogus use of
virt_to_page() on a vmalloc adddress. With CONFIG_DEBUG_VIRTUAL selected
this will be reported explicitly, and with or without CONFIG_DEBUG_VIRTUAL
the kernel will dereference a bogus address:
| ------------[ cut here ]------------
| virt_to_phys used for non-linear address: (____ptrval____) (0xffff800008000000)
| WARNING: CPU: 0 PID: 0 at arch/arm64/mm/physaddr.c:15 __virt_to_phys+0x78/0x80
| Modules linked in:
| CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.3.0-rc3-00073-g83865133300d-dirty #4
| Hardware name: linux,dummy-virt (DT)
| pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : __virt_to_phys+0x78/0x80
| lr : __virt_to_phys+0x78/0x80
| sp : ffffcd076afd3c80
| x29: ffffcd076afd3c80 x28: 0068000000000f07 x27: ffff800008000000
| x26: fffffbfff0000000 x25: fffffbffff000000 x24: ff00000000000000
| x23: ffffcd076ad3c000 x22: fffffc0000000000 x21: ffff800008000000
| x20: ffff800008004000 x19: ffff800008000000 x18: ffff800008004000
| x17: 666678302820295f x16: ffffffffffffffff x15: 0000000000000004
| x14: ffffcd076b009e88 x13: 0000000000000fff x12: 0000000000000003
| x11: 00000000ffffefff x10: c0000000ffffefff x9 : 0000000000000000
| x8 : 0000000000000000 x7 : 205d303030303030 x6 : 302e30202020205b
| x5 : ffffcd076b41d63f x4 : ffffcd076afd3827 x3 : 0000000000000000
| x2 : 0000000000000000 x1 : ffffcd076afd3a30 x0 : 000000000000004f
| Call trace:
| __virt_to_phys+0x78/0x80
| __kasan_unpoison_vmalloc+0xd4/0x478
| __vmalloc_node_range+0x77c/0x7b8
| __vmalloc_node+0x54/0x64
| init_IRQ+0x94/0xc8
| start_kernel+0x194/0x420
| __primary_switched+0xbc/0xc4
| ---[ end trace 0000000000000000 ]---
| Unable to handle kernel paging request at virtual address 03fffacbe27b8000
| Mem abort info:
| ESR = 0x0000000096000004
| EC = 0x25: DABT (current EL), IL = 32 bits
| SET = 0, FnV = 0
| EA = 0, S1PTW = 0
| FSC = 0x04: level 0 translation fault
| Data abort info:
| ISV = 0, ISS = 0x00000004
| CM = 0, WnR = 0
| swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000041bc5000
| [03fffacbe27b8000] pgd=0000000000000000, p4d=0000000000000000
| Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
| Modules linked in:
| CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 6.3.0-rc3-00073-g83865133300d-dirty #4
| Hardware name: linux,dummy-virt (DT)
| pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : __kasan_unpoison_vmalloc+0xe4/0x478
| lr : __kasan_unpoison_vmalloc+0xd4/0x478
| sp : ffffcd076afd3ca0
| x29: ffffcd076afd3ca0 x28: 0068000000000f07 x27: ffff800008000000
| x26: 0000000000000000 x25: 03fffacbe27b8000 x24: ff00000000000000
| x23: ffffcd076ad3c000 x22: fffffc0000000000 x21: ffff800008000000
| x20: ffff800008004000 x19: ffff800008000000 x18: ffff800008004000
| x17: 666678302820295f x16: ffffffffffffffff x15: 0000000000000004
| x14: ffffcd076b009e88 x13: 0000000000000fff x12: 0000000000000001
| x11: 0000800008000000 x10: ffff800008000000 x9 : ffffb2f8dee00000
| x8 : 000ffffb2f8dee00 x7 : 205d303030303030 x6 : 302e30202020205b
| x5 : ffffcd076b41d63f x4 : ffffcd076afd3827 x3 : 0000000000000000
| x2 : 0000000000000000 x1 : ffffcd076afd3a30 x0 : ffffb2f8dee00000
| Call trace:
| __kasan_unpoison_vmalloc+0xe4/0x478
| __vmalloc_node_range+0x77c/0x7b8
| __vmalloc_node+0x54/0x64
| init_IRQ+0x94/0xc8
| start_kernel+0x194/0x420
| __primary_switched+0xbc/0xc4
| Code: d34cfc08 aa1f03fa 8b081b39 d503201f (f9400328)
| ---[ end trace 0000000000000000 ]---
| Kernel panic - not syncing: Attempted to kill the idle task!
This is because init_vmalloc_pages() erroneously calls virt_to_page() on
a vmalloc address, while virt_to_page() is only valid for addresses in
the linear/direct map. Since init_vmalloc_pages() expects virtual
addresses in the vmalloc range, it must use vmalloc_to_page() rather
than virt_to_page().
We call init_vmalloc_pages() from __kasan_unpoison_vmalloc(), where we
check !is_vmalloc_or_module_addr(), suggesting that we might encounter a
non-vmalloc address. Luckily, this never happens. By design, we only
call __kasan_unpoison_vmalloc() on pointers in the vmalloc area, and I
have verified that we don't violate that expectation. Given that,
is_vmalloc_or_module_addr() must always be true for any legitimate
argument to __kasan_unpoison_vmalloc().
Correct init_vmalloc_pages() to use vmalloc_to_page(), and remove the
redundant and misleading use of is_vmalloc_or_module_addr() in
__kasan_unpoison_vmalloc().
Link: https://lkml.kernel.org/r/20230418164212.1775741-1-mark.rutland@arm.com
Fixes: 6c2f761dad7851d8 ("kasan: fix zeroing vmalloc memory with HW_TAGS")
Signed-off-by: Mark Rutland <mark.rutland(a)arm.com>
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Andrey Konovalov <andreyknvl(a)google.com>
Cc: Andrey Ryabinin <ryabinin.a.a(a)gmail.com>
Cc: Dmitry Vyukov <dvyukov(a)google.com>
Cc: Marco Elver <elver(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/kasan/hw_tags.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/kasan/hw_tags.c~kasan-hw_tags-avoid-invalid-virt_to_page
+++ a/mm/kasan/hw_tags.c
@@ -285,7 +285,7 @@ static void init_vmalloc_pages(const voi
const void *addr;
for (addr = start; addr < start + size; addr += PAGE_SIZE) {
- struct page *page = virt_to_page(addr);
+ struct page *page = vmalloc_to_page(addr);
clear_highpage_kasan_tagged(page);
}
@@ -297,7 +297,7 @@ void *__kasan_unpoison_vmalloc(const voi
u8 tag;
unsigned long redzone_start, redzone_size;
- if (!kasan_vmalloc_enabled() || !is_vmalloc_or_module_addr(start)) {
+ if (!kasan_vmalloc_enabled()) {
if (flags & KASAN_VMALLOC_INIT)
init_vmalloc_pages(start, size);
return (void *)start;
_
Patches currently in -mm which might be from mark.rutland(a)arm.com are
kasan-hw_tags-avoid-invalid-virt_to_page.patch