kernel/bounds.c is recompiled on every build, and shows the following
warning when compiling with W=1:
CC kernel/bounds.s
linux/kernel/bounds.c:16:6: warning: no previous prototype for ‘foo’ [-Wmissing-prototypes]
void foo(void)
^~~
Provide a prototype to satisfy the compiler.
Signed-off-by: Kieran Bingham <kieran.bingham+renesas(a)ideasonboard.com>
Cc: stable(a)vger.kernel.org
---
I compile all of my incremental builds with W=1, which allows me to know
instantly if I add a new compiler warning in code I generate.
This warning always comes up and seems trivial to clean up.
---
kernel/bounds.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/bounds.c b/kernel/bounds.c
index c373e887c066..60136d937800 100644
--- a/kernel/bounds.c
+++ b/kernel/bounds.c
@@ -13,6 +13,8 @@
#include <linux/log2.h>
#include <linux/spinlock_types.h>
+void foo(void);
+
void foo(void)
{
/* The enum constants to put into include/generated/bounds.h */
--
2.17.1
In the presence of multi-order entries the typical
pagevec_lookup_entries() pattern may loop forever:
while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
indices)) {
...
for (i = 0; i < pagevec_count(&pvec); i++) {
index = indices[i];
...
}
index++; /* BUG */
}
The loop updates 'index' for each index found and then increments to the
next possible page to continue the lookup. However, if the last entry in
the pagevec is multi-order then the next possible page index is more
than 1 page away. Fix this locally for the filesystem-dax case by
checking for dax-multi-order entries. Going forward new users of
multi-order entries need to be similarly careful, or we need a generic
way to report the page increment in the radix iterator.
Fixes: 5fac7408d828 ("mm, fs, dax: handle layout changes to pinned dax...")
Cc: <stable(a)vger.kernel.org>
Cc: Jan Kara <jack(a)suse.cz>
Cc: Ross Zwisler <zwisler(a)kernel.org>
Cc: Matthew Wilcox <willy(a)infradead.org>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
---
Changes in v2:
* Only update nr_pages if the last entry in the pagevec is multi-order.
fs/dax.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 4becbf168b7f..0fb270f0a0ef 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -666,6 +666,8 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
indices)) {
+ pgoff_t nr_pages = 1;
+
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *pvec_ent = pvec.pages[i];
void *entry;
@@ -680,8 +682,15 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
xa_lock_irq(&mapping->i_pages);
entry = get_unlocked_mapping_entry(mapping, index, NULL);
- if (entry)
+ if (entry) {
page = dax_busy_page(entry);
+ /*
+ * Account for multi-order entries at
+ * the end of the pagevec.
+ */
+ if (i + 1 >= pagevec_count(&pvec))
+ nr_pages = 1UL << dax_radix_order(entry);
+ }
put_unlocked_mapping_entry(mapping, index, entry);
xa_unlock_irq(&mapping->i_pages);
if (page)
@@ -696,7 +705,7 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
*/
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- index++;
+ index += nr_pages;
if (page)
break;
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From b45ba4a51cde29b2939365ef0c07ad34c8321789 Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy(a)c-s.fr>
Date: Mon, 1 Oct 2018 12:21:10 +0000
Subject: [PATCH] powerpc/lib: fix book3s/32 boot failure due to code patching
Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init
sections") accesses 'init_mem_is_free' flag too early, before the
kernel is relocated. This provokes early boot failure (before the
console is active).
As it is not necessary to do this verification that early, this
patch moves the test into patch_instruction() instead of
__patch_instruction().
This modification also has the advantage of avoiding unnecessary
remappings.
Fixes: 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections")
Cc: stable(a)vger.kernel.org # 4.13+
Signed-off-by: Christophe Leroy <christophe.leroy(a)c-s.fr>
Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au>
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 6ae2777c220d..5ffee298745f 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -28,12 +28,6 @@ static int __patch_instruction(unsigned int *exec_addr, unsigned int instr,
{
int err;
- /* Make sure we aren't patching a freed init section */
- if (init_mem_is_free && init_section_contains(exec_addr, 4)) {
- pr_debug("Skipping init section patching addr: 0x%px\n", exec_addr);
- return 0;
- }
-
__put_user_size(instr, patch_addr, 4, err);
if (err)
return err;
@@ -148,7 +142,7 @@ static inline int unmap_patch_area(unsigned long addr)
return 0;
}
-int patch_instruction(unsigned int *addr, unsigned int instr)
+static int do_patch_instruction(unsigned int *addr, unsigned int instr)
{
int err;
unsigned int *patch_addr = NULL;
@@ -188,12 +182,22 @@ out:
}
#else /* !CONFIG_STRICT_KERNEL_RWX */
-int patch_instruction(unsigned int *addr, unsigned int instr)
+static int do_patch_instruction(unsigned int *addr, unsigned int instr)
{
return raw_patch_instruction(addr, instr);
}
#endif /* CONFIG_STRICT_KERNEL_RWX */
+
+int patch_instruction(unsigned int *addr, unsigned int instr)
+{
+ /* Make sure we aren't patching a freed init section */
+ if (init_mem_is_free && init_section_contains(addr, 4)) {
+ pr_debug("Skipping init section patching addr: 0x%px\n", addr);
+ return 0;
+ }
+ return do_patch_instruction(addr, instr);
+}
NOKPROBE_SYMBOL(patch_instruction);
int patch_branch(unsigned int *addr, unsigned long target, int flags)
From: Jann Horn <jannh(a)google.com>
[ upstream commit b799207e1e1816b09e7a5920fbb2d5fcf6edd681 ]
When I wrote commit 468f6eafa6c4 ("bpf: fix 32-bit ALU op verification"), I
assumed that, in order to emulate 64-bit arithmetic with 32-bit logic, it
is sufficient to just truncate the output to 32 bits; and so I just moved
the register size coercion that used to be at the start of the function to
the end of the function.
That assumption is true for almost every op, but not for 32-bit right
shifts, because those can propagate information towards the least
significant bit. Fix it by always truncating inputs for 32-bit ops to 32
bits.
Also get rid of the coerce_reg_to_size() after the ALU op, since that has
no effect.
Fixes: 468f6eafa6c4 ("bpf: fix 32-bit ALU op verification")
Acked-by: Daniel Borkmann <daniel(a)iogearbox.net>
Signed-off-by: Jann Horn <jannh(a)google.com>
Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net>
---
kernel/bpf/verifier.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index adbe21c..82e8ede 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2865,6 +2865,15 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
u64 umin_val, umax_val;
u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
+ if (insn_bitness == 32) {
+ /* Relevant for 32-bit RSH: Information can propagate towards
+ * LSB, so it isn't sufficient to only truncate the output to
+ * 32 bits.
+ */
+ coerce_reg_to_size(dst_reg, 4);
+ coerce_reg_to_size(&src_reg, 4);
+ }
+
smin_val = src_reg.smin_value;
smax_val = src_reg.smax_value;
umin_val = src_reg.umin_value;
@@ -3100,7 +3109,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
if (BPF_CLASS(insn->code) != BPF_ALU64) {
/* 32-bit ALU ops are (32,32)->32 */
coerce_reg_to_size(dst_reg, 4);
- coerce_reg_to_size(&src_reg, 4);
}
__reg_deduce_bounds(dst_reg);
--
2.9.5
> Miklos,
>
> Seeing that it wasn't fixed in 4.18..
>
> > I've nothing against applying "new primitive: discard_new_inode() now
> > + this patch, but if it is deemed too risky at this point, we could
> > just revert the buggy commit 80ea09a002bf ("vfs: factor out
> > inode_insert5()") and its dependencies.
> >
>
> Should we propose for stable the upstream commits:
> e950564b97fd vfs: don't evict uninitialized inode
> c2b6d621c4ff new primitive: discard_new_inode()
>
> Or should we go with the independent v1 patch:
> https://patchwork.kernel.org/patch/10511969/
>
Greg,
To fix a 4.18 overlayfs regression please apply the following
3 upstream commits (in apply order):
c2b6d621c4ff new primitive: discard_new_inode()
e950564b97fd vfs: don't evict uninitialized inode
6faf05c2b2b4 ovl: set I_CREATING on inode being created
Thanks,
Amir.
From: Tang Junhui <tang.junhui.linux(a)gmail.com>
refill->end record the last key of writeback, for example, at the first
time, keys (1,128K) to (1,1024K) are flush to the backend device, but
the end key (1,1024K) is not included, since the bellow code:
if (bkey_cmp(k, refill->end) >= 0) {
ret = MAP_DONE;
goto out;
}
And in the next time when we refill writeback keybuf again, we searched
key start from (1,1024K), and got a key bigger than it, so the key
(1,1024K) missed.
This patch modify the above code, and let the end key to be included to
the writeback key buffer.
Signed-off-by: Tang Junhui <tang.junhui.linux(a)gmail.com>
Cc: stable(a)vger.kernel.org
Signed-off-by: Coly Li <colyli(a)suse.de>
---
drivers/md/bcache/btree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index e7d4817681f2..3f4211b5cd33 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -2434,7 +2434,7 @@ static int refill_keybuf_fn(struct btree_op *op, struct btree *b,
struct keybuf *buf = refill->buf;
int ret = MAP_CONTINUE;
- if (bkey_cmp(k, refill->end) >= 0) {
+ if (bkey_cmp(k, refill->end) > 0) {
ret = MAP_DONE;
goto out;
}
--
2.19.0
From: Tang Junhui <tang.junhui.linux(a)gmail.com>
When bcache device is clean, dirty keys may still exist after
journal replay, so we need to count these dirty keys even
device in clean status, otherwise after writeback, the amount
of dirty data would be incorrect.
Signed-off-by: Tang Junhui <tang.junhui.linux(a)gmail.com>
Cc: stable(a)vger.kernel.org
Signed-off-by: Coly Li <colyli(a)suse.de>
---
drivers/md/bcache/super.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index a99af19d2f91..4989c7d4d4d0 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1152,11 +1152,12 @@ int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
}
if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
- bch_sectors_dirty_init(&dc->disk);
atomic_set(&dc->has_dirty, 1);
bch_writeback_queue(dc);
}
+ bch_sectors_dirty_init(&dc->disk);
+
bch_cached_dev_run(dc);
bcache_device_link(&dc->disk, c, "bdev");
atomic_inc(&c->attached_dev_nr);
--
2.19.0
In the presence of multi-order entries the typical
pagevec_lookup_entries() pattern may loop forever:
while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
indices)) {
...
for (i = 0; i < pagevec_count(&pvec); i++) {
index = indices[i];
...
}
index++; /* BUG */
}
The loop updates 'index' for each index found and then increments to the
next possible page to continue the lookup. However, if the last entry in
the pagevec is multi-order then the next possible page index is more
than 1 page away. Fix this locally for the filesystem-dax case by
checking for dax-multi-order entries. Going forward new users of
multi-order entries need to be similarly careful, or we need a generic
way to report the page increment in the radix iterator.
Fixes: 5fac7408d828 ("mm, fs, dax: handle layout changes to pinned dax...")
Cc: <stable(a)vger.kernel.org>
Cc: Jan Kara <jack(a)suse.cz>
Cc: Ross Zwisler <zwisler(a)kernel.org>
Cc: Matthew Wilcox <willy(a)infradead.org>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
---
fs/dax.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 4becbf168b7f..c1472eede1f7 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -666,6 +666,8 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
indices)) {
+ pgoff_t nr_pages = 1;
+
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *pvec_ent = pvec.pages[i];
void *entry;
@@ -680,8 +682,11 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
xa_lock_irq(&mapping->i_pages);
entry = get_unlocked_mapping_entry(mapping, index, NULL);
- if (entry)
+ if (entry) {
page = dax_busy_page(entry);
+ /* account for multi-order entries */
+ nr_pages = 1UL << dax_radix_order(entry);
+ }
put_unlocked_mapping_entry(mapping, index, entry);
xa_unlock_irq(&mapping->i_pages);
if (page)
@@ -696,7 +701,7 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
*/
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- index++;
+ index += nr_pages;
if (page)
break;
From: "H. Peter Anvin (Intel)" <hpa(a)zytor.com>
It turns out that Alpha is the only architecture that never
implemented BOTHER and IBSHIFT, which is otherwise ages old. This is
one thing that has held up glibc support for this feature (all other
architectures have supported these for about a decade, at least before
the current 3.2 glibc cutoff.)
Furthermore, in the process of dealing with this, I discovered that
the current code in tty_baudrate.c can read past the end of the
baud_table[] on Alpha and PowerPC. The second patch in this series
fixes that, but it also cleans up the code substantially by
auto-generating the table and, since all architectures now have them,
removing all conditionals for BOTHER and IBSHIFT existing.
Tagging for stable because these are concrete problems. I have a much
bigger update in process, nearly done, which will clean up a lot of
duplicated code and make the uapi headers usable for libc, but that is
not critical on the same level.
Tested on x86, compile-tested on Alpha.
Signed-off-by: H. Peter Anvin (Intel) <hpa(a)zytor.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Jiri Slaby <jslaby(a)suse.com>
Cc: Al Viro <viro(a)zeniv.linux.org.uk>
Cc: Richard Henderson <rth(a)twiddle.net>
Cc: Ivan Kokshaysky <ink(a)jurassic.park.msu.ru>
Cc: Matt Turner <mattst88(a)gmail.com>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Kate Stewart <kstewart(a)linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne(a)nexb.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Eugene Syromiatnikov <esyr(a)redhat.com>
Cc: <linux-alpha(a)vger.kernel.org>
Cc: <linux-serial(a)vger.kernel.org>
Cc: Johan Hovold <johan(a)kernel.org>
Cc: Alan Cox <alan(a)lxorguk.ukuu.org.uk>
Cc: Benjamin Herrenschmidt <benh(a)kernel.crashing.org>
Cc: Paul Mackerras <paulus(a)samba.org>
Cc: Michael Ellerman <mpe(a)ellerman.id.au>
Cc: <stable(a)vger.kernel.org>
---
arch/alpha/include/asm/termios.h | 8 +-
arch/alpha/include/uapi/asm/ioctls.h | 5 +
arch/alpha/include/uapi/asm/termbits.h | 17 +++
drivers/tty/.gitignore | 1 +
drivers/tty/Makefile | 16 +++
drivers/tty/bmacros.c | 2 +
drivers/tty/tty_baudrate.c | 190 +++++++++++++--------------------
7 files changed, 122 insertions(+), 117 deletions(-)
The code cleaning transaction's lists of checkpoint buffers has a bug
where it increases bh refcount only after releasing
journal->j_list_lock. Thus the following race is possible:
CPU0 CPU1
jbd2_log_do_checkpoint()
jbd2_journal_try_to_free_buffers()
__journal_try_to_free_buffer(bh)
...
while (transaction->t_checkpoint_io_list)
...
if (buffer_locked(bh)) {
<-- IO completes now, buffer gets unlocked -->
spin_unlock(&journal->j_list_lock);
spin_lock(&journal->j_list_lock);
__jbd2_journal_remove_checkpoint(jh);
spin_unlock(&journal->j_list_lock);
try_to_free_buffers(page);
get_bh(bh) <-- accesses freed bh
Fix the problem by grabbing bh reference before unlocking
journal->j_list_lock.
Fixes: dc6e8d669cf5cb3ff84707c372c0a2a8a5e80845
Fixes: be1158cc615fd723552f0d9912087423c7cadda5
Reported-by: syzbot+7f4a27091759e2fe7453(a)syzkaller.appspotmail.com
CC: stable(a)vger.kernel.org
Signed-off-by: Jan Kara <jack(a)suse.cz>
---
fs/jbd2/checkpoint.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index c125d662777c..26f8d7e46462 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -251,8 +251,8 @@ int jbd2_log_do_checkpoint(journal_t *journal)
bh = jh2bh(jh);
if (buffer_locked(bh)) {
- spin_unlock(&journal->j_list_lock);
get_bh(bh);
+ spin_unlock(&journal->j_list_lock);
wait_on_buffer(bh);
/* the journal_head may have gone by now */
BUFFER_TRACE(bh, "brelse");
@@ -333,8 +333,8 @@ int jbd2_log_do_checkpoint(journal_t *journal)
jh = transaction->t_checkpoint_io_list;
bh = jh2bh(jh);
if (buffer_locked(bh)) {
- spin_unlock(&journal->j_list_lock);
get_bh(bh);
+ spin_unlock(&journal->j_list_lock);
wait_on_buffer(bh);
/* the journal_head may have gone by now */
BUFFER_TRACE(bh, "brelse");
--
2.16.4
From: Ashish Samant <ashish.samant(a)oracle.com>
Subject: ocfs2: fix locking for res->tracking and dlm->tracking_list
In dlm_init_lockres() we access and modify res->tracking and
dlm->tracking_list without holding dlm->track_lock. This can cause list
corruptions and can end up in kernel panic.
Fix this by locking res->tracking and dlm->tracking_list with
dlm->track_lock instead of dlm->spinlock.
Link: http://lkml.kernel.org/r/1529951192-4686-1-git-send-email-ashish.samant@ora…
Signed-off-by: Ashish Samant <ashish.samant(a)oracle.com>
Reviewed-by: Changwei Ge <ge.changwei(a)h3c.com>
Acked-by: Joseph Qi <jiangqi903(a)gmail.com>
Acked-by: Jun Piao <piaojun(a)huawei.com>
Cc: Mark Fasheh <mark(a)fasheh.com>
Cc: Joel Becker <jlbec(a)evilplan.org>
Cc: Junxiao Bi <junxiao.bi(a)oracle.com>
Cc: Changwei Ge <ge.changwei(a)h3c.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
fs/ocfs2/dlm/dlmmaster.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/ocfs2/dlm/dlmmaster.c~ocfs2-fix-locking-for-res-tracking-and-dlm-tracking_list
+++ a/fs/ocfs2/dlm/dlmmaster.c
@@ -584,9 +584,9 @@ static void dlm_init_lockres(struct dlm_
res->last_used = 0;
- spin_lock(&dlm->spinlock);
+ spin_lock(&dlm->track_lock);
list_add_tail(&res->tracking, &dlm->tracking_list);
- spin_unlock(&dlm->spinlock);
+ spin_unlock(&dlm->track_lock);
memset(res->lvb, 0, DLM_LVB_LEN);
memset(res->refmap, 0, sizeof(res->refmap));
_
From: Jann Horn <jannh(a)google.com>
Subject: mm/vmstat.c: skip NR_TLB_REMOTE_FLUSH* properly
5dd0b16cdaff ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even
on UP") made the availability of the NR_TLB_REMOTE_FLUSH* counters inside
the kernel unconditional to reduce #ifdef soup, but (either to avoid
showing dummy zero counters to userspace, or because that code was missed)
didn't update the vmstat_array, meaning that all following counters would
be shown with incorrect values.
This only affects kernel builds with
CONFIG_VM_EVENT_COUNTERS=y && CONFIG_DEBUG_TLBFLUSH=y && CONFIG_SMP=n.
Link: http://lkml.kernel.org/r/20181001143138.95119-2-jannh@google.com
Fixes: 5dd0b16cdaff ("mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even on UP")
Signed-off-by: Jann Horn <jannh(a)google.com>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Reviewed-by: Andrew Morton <akpm(a)linux-foundation.org>
Acked-by: Michal Hocko <mhocko(a)suse.com>
Acked-by: Roman Gushchin <guro(a)fb.com>
Cc: Davidlohr Bueso <dave(a)stgolabs.net>
Cc: Oleg Nesterov <oleg(a)redhat.com>
Cc: Christoph Lameter <clameter(a)sgi.com>
Cc: Kemi Wang <kemi.wang(a)intel.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Ingo Molnar <mingo(a)kernel.org>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/vmstat.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/vmstat.c~mm-vmstat-skip-nr_tlb_remote_flush-properly
+++ a/mm/vmstat.c
@@ -1275,6 +1275,9 @@ const char * const vmstat_text[] = {
#ifdef CONFIG_SMP
"nr_tlb_remote_flush",
"nr_tlb_remote_flush_received",
+#else
+ "", /* nr_tlb_remote_flush */
+ "", /* nr_tlb_remote_flush_received */
#endif /* CONFIG_SMP */
"nr_tlb_local_flush_all",
"nr_tlb_local_flush_one",
_
From: Jann Horn <jannh(a)google.com>
Subject: proc: restrict kernel stack dumps to root
Currently, you can use /proc/self/task/*/stack to cause a stack walk on
a task you control while it is running on another CPU. That means that
the stack can change under the stack walker. The stack walker does
have guards against going completely off the rails and into random
kernel memory, but it can interpret random data from your kernel stack
as instruction pointers and stack pointers. This can cause exposure of
kernel stack contents to userspace.
Restrict the ability to inspect kernel stacks of arbitrary tasks to root
in order to prevent a local attacker from exploiting racy stack unwinding
to leak kernel task stack contents. See the added comment for a longer
rationale.
There don't seem to be any users of this userspace API that can't
gracefully bail out if reading from the file fails. Therefore, I believe
that this change is unlikely to break things. In the case that this patch
does end up needing a revert, the next-best solution might be to fake a
single-entry stack based on wchan.
Link: http://lkml.kernel.org/r/20180927153316.200286-1-jannh@google.com
Fixes: 2ec220e27f50 ("proc: add /proc/*/stack")
Signed-off-by: Jann Horn <jannh(a)google.com>
Acked-by: Kees Cook <keescook(a)chromium.org>
Cc: Alexey Dobriyan <adobriyan(a)gmail.com>
Cc: Ken Chen <kenchen(a)google.com>
Cc: Will Deacon <will.deacon(a)arm.com>
Cc: Laura Abbott <labbott(a)redhat.com>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Catalin Marinas <catalin.marinas(a)arm.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: "H . Peter Anvin" <hpa(a)zytor.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
fs/proc/base.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
--- a/fs/proc/base.c~proc-restrict-kernel-stack-dumps-to-root
+++ a/fs/proc/base.c
@@ -407,6 +407,20 @@ static int proc_pid_stack(struct seq_fil
unsigned long *entries;
int err;
+ /*
+ * The ability to racily run the kernel stack unwinder on a running task
+ * and then observe the unwinder output is scary; while it is useful for
+ * debugging kernel issues, it can also allow an attacker to leak kernel
+ * stack contents.
+ * Doing this in a manner that is at least safe from races would require
+ * some work to ensure that the remote task can not be scheduled; and
+ * even then, this would still expose the unwinder as local attack
+ * surface.
+ * Therefore, this interface is restricted to root.
+ */
+ if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
+ return -EACCES;
+
entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
GFP_KERNEL);
if (!entries)
_
From: "Kirill A. Shutemov" <kirill.shutemov(a)linux.intel.com>
Subject: mm, thp: fix mlocking THP page with migration enabled
A transparent huge page is represented by a single entry on an LRU list.
Therefore, we can only make unevictable an entire compound page, not
individual subpages.
If a user tries to mlock() part of a huge page, we want the rest of the
page to be reclaimable.
We handle this by keeping PTE-mapped huge pages on normal LRU lists: the
PMD on border of VM_LOCKED VMA will be split into PTE table.
Introduction of THP migration breaks[1] the rules around mlocking THP
pages. If we had a single PMD mapping of the page in mlocked VMA, the
page will get mlocked, regardless of PTE mappings of the page.
For tmpfs/shmem it's easy to fix by checking PageDoubleMap() in
remove_migration_pmd().
Anon THP pages can only be shared between processes via fork(). Mlocked
page can only be shared if parent mlocked it before forking, otherwise CoW
will be triggered on mlock().
For Anon-THP, we can fix the issue by munlocking the page on removing PTE
migration entry for the page. PTEs for the page will always come after
mlocked PMD: rmap walks VMAs from oldest to newest.
Test-case:
#include <unistd.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <linux/mempolicy.h>
#include <numaif.h>
int main(void)
{
unsigned long nodemask = 4;
void *addr;
addr = mmap((void *)0x20000000UL, 2UL << 20, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED, -1, 0);
if (fork()) {
wait(NULL);
return 0;
}
mlock(addr, 4UL << 10);
mbind(addr, 2UL << 20, MPOL_PREFERRED | MPOL_F_RELATIVE_NODES,
&nodemask, 4, MPOL_MF_MOVE);
return 0;
}
[1] https://lkml.kernel.org/r/CAOMGZ=G52R-30rZvhGxEbkTw7rLLwBGadVYeo--iizcD3upL…
Link: http://lkml.kernel.org/r/20180917133816.43995-1-kirill.shutemov@linux.intel…
Fixes: 616b8371539a ("mm: thp: enable thp migration in generic path")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com>
Reported-by: Vegard Nossum <vegard.nossum(a)oracle.com>
Reviewed-by: Zi Yan <zi.yan(a)cs.rutgers.edu>
Cc: Naoya Horiguchi <n-horiguchi(a)ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: Andrea Arcangeli <aarcange(a)redhat.com>
Cc: <stable(a)vger.kernel.org> [4.14+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/huge_memory.c | 2 +-
mm/migrate.c | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
--- a/mm/huge_memory.c~mm-thp-fix-mlocking-thp-page-with-migration-enabled
+++ a/mm/huge_memory.c
@@ -2931,7 +2931,7 @@ void remove_migration_pmd(struct page_vm
else
page_add_file_rmap(new, true);
set_pmd_at(mm, mmun_start, pvmw->pmd, pmde);
- if (vma->vm_flags & VM_LOCKED)
+ if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new))
mlock_vma_page(new);
update_mmu_cache_pmd(vma, address, pvmw->pmd);
}
--- a/mm/migrate.c~mm-thp-fix-mlocking-thp-page-with-migration-enabled
+++ a/mm/migrate.c
@@ -275,6 +275,9 @@ static bool remove_migration_pte(struct
if (vma->vm_flags & VM_LOCKED && !PageTransCompound(new))
mlock_vma_page(new);
+ if (PageTransHuge(page) && PageMlocked(page))
+ clear_page_mlock(page);
+
/* No need to invalidate - it was non-present before */
update_mmu_cache(vma, pvmw.address, pvmw.pte);
}
_
From: Mike Kravetz <mike.kravetz(a)oracle.com>
Subject: mm: migration: fix migration of huge PMD shared pages
The page migration code employs try_to_unmap() to try and unmap the source
page. This is accomplished by using rmap_walk to find all vmas where the
page is mapped. This search stops when page mapcount is zero. For shared
PMD huge pages, the page map count is always 1 no matter the number of
mappings. Shared mappings are tracked via the reference count of the PMD
page. Therefore, try_to_unmap stops prematurely and does not completely
unmap all mappings of the source page.
This problem can result is data corruption as writes to the original
source page can happen after contents of the page are copied to the target
page. Hence, data is lost.
This problem was originally seen as DB corruption of shared global areas
after a huge page was soft offlined due to ECC memory errors. DB
developers noticed they could reproduce the issue by (hotplug) offlining
memory used to back huge pages. A simple testcase can reproduce the
problem by creating a shared PMD mapping (note that this must be at least
PUD_SIZE in size and PUD_SIZE aligned (1GB on x86)), and using
migrate_pages() to migrate process pages between nodes while continually
writing to the huge pages being migrated.
To fix, have the try_to_unmap_one routine check for huge PMD sharing by
calling huge_pmd_unshare for hugetlbfs huge pages. If it is a shared
mapping it will be 'unshared' which removes the page table entry and drops
the reference on the PMD page. After this, flush caches and TLB.
mmu notifiers are called before locking page tables, but we can not be
sure of PMD sharing until page tables are locked. Therefore, check for
the possibility of PMD sharing before locking so that notifiers can
prepare for the worst possible case.
Link: http://lkml.kernel.org/r/20180823205917.16297-2-mike.kravetz@oracle.com
[mike.kravetz(a)oracle.com: make _range_in_vma() a static inline]
Link: http://lkml.kernel.org/r/6063f215-a5c8-2f0c-465a-2c515ddc952d@oracle.com
Fixes: 39dde65c9940 ("shared page table for hugetlb page")
Signed-off-by: Mike Kravetz <mike.kravetz(a)oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi(a)ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko(a)suse.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: Davidlohr Bueso <dave(a)stgolabs.net>
Cc: Jerome Glisse <jglisse(a)redhat.com>
Cc: Mike Kravetz <mike.kravetz(a)oracle.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
include/linux/hugetlb.h | 14 ++++++++++++
include/linux/mm.h | 6 +++++
mm/hugetlb.c | 37 +++++++++++++++++++++++++++++++--
mm/rmap.c | 42 +++++++++++++++++++++++++++++++++++---
4 files changed, 94 insertions(+), 5 deletions(-)
--- a/include/linux/hugetlb.h~mm-migration-fix-migration-of-huge-pmd-shared-pages
+++ a/include/linux/hugetlb.h
@@ -140,6 +140,8 @@ pte_t *huge_pte_alloc(struct mm_struct *
pte_t *huge_pte_offset(struct mm_struct *mm,
unsigned long addr, unsigned long sz);
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep);
+void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
+ unsigned long *start, unsigned long *end);
struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
int write);
struct page *follow_huge_pd(struct vm_area_struct *vma,
@@ -170,6 +172,18 @@ static inline unsigned long hugetlb_tota
return 0;
}
+static inline int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr,
+ pte_t *ptep)
+{
+ return 0;
+}
+
+static inline void adjust_range_if_pmd_sharing_possible(
+ struct vm_area_struct *vma,
+ unsigned long *start, unsigned long *end)
+{
+}
+
#define follow_hugetlb_page(m,v,p,vs,a,b,i,w,n) ({ BUG(); 0; })
#define follow_huge_addr(mm, addr, write) ERR_PTR(-EINVAL)
#define copy_hugetlb_page_range(src, dst, vma) ({ BUG(); 0; })
--- a/include/linux/mm.h~mm-migration-fix-migration-of-huge-pmd-shared-pages
+++ a/include/linux/mm.h
@@ -2455,6 +2455,12 @@ static inline struct vm_area_struct *fin
return vma;
}
+static inline bool range_in_vma(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ return (vma && vma->vm_start <= start && end <= vma->vm_end);
+}
+
#ifdef CONFIG_MMU
pgprot_t vm_get_page_prot(unsigned long vm_flags);
void vma_set_page_prot(struct vm_area_struct *vma);
--- a/mm/hugetlb.c~mm-migration-fix-migration-of-huge-pmd-shared-pages
+++ a/mm/hugetlb.c
@@ -4545,13 +4545,41 @@ static bool vma_shareable(struct vm_area
/*
* check on proper vm_flags and page table alignment
*/
- if (vma->vm_flags & VM_MAYSHARE &&
- vma->vm_start <= base && end <= vma->vm_end)
+ if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
return true;
return false;
}
/*
+ * Determine if start,end range within vma could be mapped by shared pmd.
+ * If yes, adjust start and end to cover range associated with possible
+ * shared pmd mappings.
+ */
+void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
+ unsigned long *start, unsigned long *end)
+{
+ unsigned long check_addr = *start;
+
+ if (!(vma->vm_flags & VM_MAYSHARE))
+ return;
+
+ for (check_addr = *start; check_addr < *end; check_addr += PUD_SIZE) {
+ unsigned long a_start = check_addr & PUD_MASK;
+ unsigned long a_end = a_start + PUD_SIZE;
+
+ /*
+ * If sharing is possible, adjust start/end if necessary.
+ */
+ if (range_in_vma(vma, a_start, a_end)) {
+ if (a_start < *start)
+ *start = a_start;
+ if (a_end > *end)
+ *end = a_end;
+ }
+ }
+}
+
+/*
* Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
* and returns the corresponding pte. While this is not necessary for the
* !shared pmd case because we can allocate the pmd later as well, it makes the
@@ -4648,6 +4676,11 @@ int huge_pmd_unshare(struct mm_struct *m
{
return 0;
}
+
+void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
+ unsigned long *start, unsigned long *end)
+{
+}
#define want_pmd_share() (0)
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
--- a/mm/rmap.c~mm-migration-fix-migration-of-huge-pmd-shared-pages
+++ a/mm/rmap.c
@@ -1362,11 +1362,21 @@ static bool try_to_unmap_one(struct page
}
/*
- * We have to assume the worse case ie pmd for invalidation. Note that
- * the page can not be free in this function as call of try_to_unmap()
- * must hold a reference on the page.
+ * For THP, we have to assume the worse case ie pmd for invalidation.
+ * For hugetlb, it could be much worse if we need to do pud
+ * invalidation in the case of pmd sharing.
+ *
+ * Note that the page can not be free in this function as call of
+ * try_to_unmap() must hold a reference on the page.
*/
end = min(vma->vm_end, start + (PAGE_SIZE << compound_order(page)));
+ if (PageHuge(page)) {
+ /*
+ * If sharing is possible, start and end will be adjusted
+ * accordingly.
+ */
+ adjust_range_if_pmd_sharing_possible(vma, &start, &end);
+ }
mmu_notifier_invalidate_range_start(vma->vm_mm, start, end);
while (page_vma_mapped_walk(&pvmw)) {
@@ -1409,6 +1419,32 @@ static bool try_to_unmap_one(struct page
subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte);
address = pvmw.address;
+ if (PageHuge(page)) {
+ if (huge_pmd_unshare(mm, &address, pvmw.pte)) {
+ /*
+ * huge_pmd_unshare unmapped an entire PMD
+ * page. There is no way of knowing exactly
+ * which PMDs may be cached for this mm, so
+ * we must flush them all. start/end were
+ * already adjusted above to cover this range.
+ */
+ flush_cache_range(vma, start, end);
+ flush_tlb_range(vma, start, end);
+ mmu_notifier_invalidate_range(mm, start, end);
+
+ /*
+ * The ref count of the PMD page was dropped
+ * which is part of the way map counting
+ * is done for shared PMDs. Return 'true'
+ * here. When there is no other sharing,
+ * huge_pmd_unshare returns false and we will
+ * unmap the actual page and drop map count
+ * to zero.
+ */
+ page_vma_mapped_walk_done(&pvmw);
+ break;
+ }
+ }
if (IS_ENABLED(CONFIG_MIGRATION) &&
(flags & TTU_MIGRATION) &&
_