The quilt patch titled
Subject: nilfs2: fix underflow in second superblock position calculations
has been removed from the -mm tree. Its filename was
nilfs2-fix-underflow-in-second-superblock-position-calculations.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke(a)gmail.com>
Subject: nilfs2: fix underflow in second superblock position calculations
Date: Wed, 15 Feb 2023 07:40:43 +0900
Macro NILFS_SB2_OFFSET_BYTES, which computes the position of the second
superblock, underflows when the argument device size is less than 4096
bytes. Therefore, when using this macro, it is necessary to check in
advance that the device size is not less than a lower limit, or at least
that underflow does not occur.
The current nilfs2 implementation lacks this check, causing out-of-bound
block access when mounting devices smaller than 4096 bytes:
I/O error, dev loop0, sector 36028797018963960 op 0x0:(READ) flags 0x0
phys_seg 1 prio class 2
NILFS (loop0): unable to read secondary superblock (blocksize = 1024)
In addition, when trying to resize the filesystem to a size below 4096
bytes, this underflow occurs in nilfs_resize_fs(), passing a huge number
of segments to nilfs_sufile_resize(), corrupting parameters such as the
number of segments in superblocks. This causes excessive loop iterations
in nilfs_sufile_resize() during a subsequent resize ioctl, causing
semaphore ns_segctor_sem to block for a long time and hang the writer
thread:
INFO: task segctord:5067 blocked for more than 143 seconds.
Not tainted 6.2.0-rc8-syzkaller-00015-gf6feea56f66d #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:segctord state:D stack:23456 pid:5067 ppid:2
flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5293 [inline]
__schedule+0x1409/0x43f0 kernel/sched/core.c:6606
schedule+0xc3/0x190 kernel/sched/core.c:6682
rwsem_down_write_slowpath+0xfcf/0x14a0 kernel/locking/rwsem.c:1190
nilfs_transaction_lock+0x25c/0x4f0 fs/nilfs2/segment.c:357
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2486 [inline]
nilfs_segctor_thread+0x52f/0x1140 fs/nilfs2/segment.c:2570
kthread+0x270/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>
...
Call Trace:
<TASK>
folio_mark_accessed+0x51c/0xf00 mm/swap.c:515
__nilfs_get_page_block fs/nilfs2/page.c:42 [inline]
nilfs_grab_buffer+0x3d3/0x540 fs/nilfs2/page.c:61
nilfs_mdt_submit_block+0xd7/0x8f0 fs/nilfs2/mdt.c:121
nilfs_mdt_read_block+0xeb/0x430 fs/nilfs2/mdt.c:176
nilfs_mdt_get_block+0x12d/0xbb0 fs/nilfs2/mdt.c:251
nilfs_sufile_get_segment_usage_block fs/nilfs2/sufile.c:92 [inline]
nilfs_sufile_truncate_range fs/nilfs2/sufile.c:679 [inline]
nilfs_sufile_resize+0x7a3/0x12b0 fs/nilfs2/sufile.c:777
nilfs_resize_fs+0x20c/0xed0 fs/nilfs2/super.c:422
nilfs_ioctl_resize fs/nilfs2/ioctl.c:1033 [inline]
nilfs_ioctl+0x137c/0x2440 fs/nilfs2/ioctl.c:1301
...
This fixes these issues by inserting appropriate minimum device size
checks or anti-underflow checks, depending on where the macro is used.
Link: https://lkml.kernel.org/r/0000000000004e1dfa05f4a48e6b@google.com
Link: https://lkml.kernel.org/r/20230214224043.24141-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com>
Reported-by: <syzbot+f0c4082ce5ebebdac63b(a)syzkaller.appspotmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
--- a/fs/nilfs2/ioctl.c~nilfs2-fix-underflow-in-second-superblock-position-calculations
+++ a/fs/nilfs2/ioctl.c
@@ -1114,7 +1114,14 @@ static int nilfs_ioctl_set_alloc_range(s
minseg = range[0] + segbytes - 1;
do_div(minseg, segbytes);
+
+ if (range[1] < 4096)
+ goto out;
+
maxseg = NILFS_SB2_OFFSET_BYTES(range[1]);
+ if (maxseg < segbytes)
+ goto out;
+
do_div(maxseg, segbytes);
maxseg--;
--- a/fs/nilfs2/super.c~nilfs2-fix-underflow-in-second-superblock-position-calculations
+++ a/fs/nilfs2/super.c
@@ -409,6 +409,15 @@ int nilfs_resize_fs(struct super_block *
goto out;
/*
+ * Prevent underflow in second superblock position calculation.
+ * The exact minimum size check is done in nilfs_sufile_resize().
+ */
+ if (newsize < 4096) {
+ ret = -ENOSPC;
+ goto out;
+ }
+
+ /*
* Write lock is required to protect some functions depending
* on the number of segments, the number of reserved segments,
* and so forth.
--- a/fs/nilfs2/the_nilfs.c~nilfs2-fix-underflow-in-second-superblock-position-calculations
+++ a/fs/nilfs2/the_nilfs.c
@@ -544,9 +544,15 @@ static int nilfs_load_super_block(struct
{
struct nilfs_super_block **sbp = nilfs->ns_sbp;
struct buffer_head **sbh = nilfs->ns_sbh;
- u64 sb2off = NILFS_SB2_OFFSET_BYTES(bdev_nr_bytes(nilfs->ns_bdev));
+ u64 sb2off, devsize = bdev_nr_bytes(nilfs->ns_bdev);
int valid[2], swp = 0;
+ if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) {
+ nilfs_err(sb, "device size too small");
+ return -EINVAL;
+ }
+ sb2off = NILFS_SB2_OFFSET_BYTES(devsize);
+
sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
&sbh[0]);
sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]);
_
Patches currently in -mm which might be from konishi.ryusuke(a)gmail.com are
The quilt patch titled
Subject: hugetlb: check for undefined shift on 32 bit architectures
has been removed from the -mm tree. Its filename was
hugetlb-check-for-undefined-shift-on-32-bit-architectures.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Mike Kravetz <mike.kravetz(a)oracle.com>
Subject: hugetlb: check for undefined shift on 32 bit architectures
Date: Wed, 15 Feb 2023 17:35:42 -0800
Users can specify the hugetlb page size in the mmap, shmget and
memfd_create system calls. This is done by using 6 bits within the flags
argument to encode the base-2 logarithm of the desired page size. The
routine hstate_sizelog() uses the log2 value to find the corresponding
hugetlb hstate structure. Converting the log2 value (page_size_log) to
potential hugetlb page size is the simple statement:
1UL << page_size_log
Because only 6 bits are used for page_size_log, the left shift can not be
greater than 63. This is fine on 64 bit architectures where a long is 64
bits. However, if a value greater than 31 is passed on a 32 bit
architecture (where long is 32 bits) the shift will result in undefined
behavior. This was generally not an issue as the result of the undefined
shift had to exactly match hugetlb page size to proceed.
Recent improvements in runtime checking have resulted in this undefined
behavior throwing errors such as reported below.
Fix by comparing page_size_log to BITS_PER_LONG before doing shift.
Link: https://lkml.kernel.org/r/20230216013542.138708-1-mike.kravetz@oracle.com
Link: https://lore.kernel.org/lkml/CA+G9fYuei_Tr-vN9GS7SfFyU1y9hNysnf=PB7kT0=yv4M…
Fixes: 42d7395feb56 ("mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB")
Signed-off-by: Mike Kravetz <mike.kravetz(a)oracle.com>
Reported-by: Naresh Kamboju <naresh.kamboju(a)linaro.org>
Reviewed-by: Jesper Juhl <jesperjuhl76(a)gmail.com>
Acked-by: Muchun Song <songmuchun(a)bytedance.com>
Tested-by: Linux Kernel Functional Testing <lkft(a)linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju(a)linaro.org>
Cc: Anders Roxell <anders.roxell(a)linaro.org>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Sasha Levin <sashal(a)kernel.org>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
--- a/include/linux/hugetlb.h~hugetlb-check-for-undefined-shift-on-32-bit-architectures
+++ a/include/linux/hugetlb.h
@@ -743,7 +743,10 @@ static inline struct hstate *hstate_size
if (!page_size_log)
return &default_hstate;
- return size_to_hstate(1UL << page_size_log);
+ if (page_size_log < BITS_PER_LONG)
+ return size_to_hstate(1UL << page_size_log);
+
+ return NULL;
}
static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
_
Patches currently in -mm which might be from mike.kravetz(a)oracle.com are
The quilt patch titled
Subject: mm/migrate: fix wrongly apply write bit after mkdirty on sparc64
has been removed from the -mm tree. Its filename was
mm-migrate-fix-wrongly-apply-write-bit-after-mkdirty-on-sparc64.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Peter Xu <peterx(a)redhat.com>
Subject: mm/migrate: fix wrongly apply write bit after mkdirty on sparc64
Date: Thu, 16 Feb 2023 10:30:59 -0500
Nick Bowler reported another sparc64 breakage after the young/dirty
persistent work for page migration (per "Link:" below). That's after a
similar report [2].
It turns out page migration was overlooked, and it wasn't failing before
because page migration was not enabled in the initial report test
environment.
David proposed another way [2] to fix this from sparc64 side, but that
patch didn't land somehow. Neither did I check whether there's any other
arch that has similar issues.
Let's fix it for now as simple as moving the write bit handling to be
after dirty, like what we did before.
Note: this is based on mm-unstable, because the breakage was since 6.1 and
we're at a very late stage of 6.2 (-rc8), so I assume for this specific
case we should target this at 6.3.
[1] https://lore.kernel.org/all/20221021160603.GA23307@u164.east.ru/
[2] https://lore.kernel.org/all/20221212130213.136267-1-david@redhat.com/
Link: https://lkml.kernel.org/r/20230216153059.256739-1-peterx@redhat.com
Fixes: 2e3468778dbe ("mm: remember young/dirty bit for page migrations")
Link: https://lore.kernel.org/all/CADyTPExpEqaJiMGoV+Z6xVgL50ZoMJg49B10LcZ=8eg19u…
Signed-off-by: Peter Xu <peterx(a)redhat.com>
Reported-by: Nick Bowler <nbowler(a)draconx.ca>
Acked-by: David Hildenbrand <david(a)redhat.com>
Tested-by: Nick Bowler <nbowler(a)draconx.ca>
Cc: <regressions(a)lists.linux.dev>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
--- a/mm/huge_memory.c~mm-migrate-fix-wrongly-apply-write-bit-after-mkdirty-on-sparc64
+++ a/mm/huge_memory.c
@@ -3272,8 +3272,6 @@ void remove_migration_pmd(struct page_vm
pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot));
if (pmd_swp_soft_dirty(*pvmw->pmd))
pmde = pmd_mksoft_dirty(pmde);
- if (is_writable_migration_entry(entry))
- pmde = maybe_pmd_mkwrite(pmde, vma);
if (pmd_swp_uffd_wp(*pvmw->pmd))
pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde));
if (!is_migration_entry_young(entry))
@@ -3281,6 +3279,10 @@ void remove_migration_pmd(struct page_vm
/* NOTE: this may contain setting soft-dirty on some archs */
if (PageDirty(new) && is_migration_entry_dirty(entry))
pmde = pmd_mkdirty(pmde);
+ if (is_writable_migration_entry(entry))
+ pmde = maybe_pmd_mkwrite(pmde, vma);
+ else
+ pmde = pmd_wrprotect(pmde);
if (PageAnon(new)) {
rmap_t rmap_flags = RMAP_COMPOUND;
--- a/mm/migrate.c~mm-migrate-fix-wrongly-apply-write-bit-after-mkdirty-on-sparc64
+++ a/mm/migrate.c
@@ -224,6 +224,8 @@ static bool remove_migration_pte(struct
pte = maybe_mkwrite(pte, vma);
else if (pte_swp_uffd_wp(*pvmw.pte))
pte = pte_mkuffd_wp(pte);
+ else
+ pte = pte_wrprotect(pte);
if (folio_test_anon(folio) && !is_readable_migration_entry(entry))
rmap_flags |= RMAP_EXCLUSIVE;
_
Patches currently in -mm which might be from peterx(a)redhat.com are
mm-uffd-fix-comment-in-handling-pte-markers.patch