The patch below does not apply to the 4.4-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 ea7e0480a4b695d0aa6b3fa99bd658a003122113 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton(a)mips.com>
Date: Tue, 25 Sep 2018 15:51:26 -0700
Subject: [PATCH] MIPS: VDSO: Always map near top of user memory
When using the legacy mmap layout, for example triggered using ulimit -s
unlimited, get_unmapped_area() fills memory from bottom to top starting
from a fairly low address near TASK_UNMAPPED_BASE.
This placement is suboptimal if the user application wishes to allocate
large amounts of heap memory using the brk syscall. With the VDSO being
located low in the user's virtual address space, the amount of space
available for access using brk is limited much more than it was prior to
the introduction of the VDSO.
For example:
# ulimit -s unlimited; cat /proc/self/maps
00400000-004ec000 r-xp 00000000 08:00 71436 /usr/bin/coreutils
004fc000-004fd000 rwxp 000ec000 08:00 71436 /usr/bin/coreutils
004fd000-0050f000 rwxp 00000000 00:00 0
00cc3000-00ce4000 rwxp 00000000 00:00 0 [heap]
2ab96000-2ab98000 r--p 00000000 00:00 0 [vvar]
2ab98000-2ab99000 r-xp 00000000 00:00 0 [vdso]
2ab99000-2ab9d000 rwxp 00000000 00:00 0
...
Resolve this by adjusting STACK_TOP to reserve space for the VDSO &
providing an address hint to get_unmapped_area() causing it to use this
space even when using the legacy mmap layout.
We reserve enough space for the VDSO, plus 1MB or 256MB for 32 bit & 64
bit systems respectively within which we randomize the VDSO base
address. Previously this randomization was taken care of by the mmap
base address randomization performed by arch_mmap_rnd(). The 1MB & 256MB
sizes are somewhat arbitrary but chosen such that we have some
randomization without taking up too much of the user's virtual address
space, which is often in short supply for 32 bit systems.
With this the VDSO is always mapped at a high address, leaving lots of
space for statically linked programs to make use of brk:
# ulimit -s unlimited; cat /proc/self/maps
00400000-004ec000 r-xp 00000000 08:00 71436 /usr/bin/coreutils
004fc000-004fd000 rwxp 000ec000 08:00 71436 /usr/bin/coreutils
004fd000-0050f000 rwxp 00000000 00:00 0
00c28000-00c49000 rwxp 00000000 00:00 0 [heap]
...
7f67c000-7f69d000 rwxp 00000000 00:00 0 [stack]
7f7fc000-7f7fd000 rwxp 00000000 00:00 0
7fcf1000-7fcf3000 r--p 00000000 00:00 0 [vvar]
7fcf3000-7fcf4000 r-xp 00000000 00:00 0 [vdso]
Signed-off-by: Paul Burton <paul.burton(a)mips.com>
Reported-by: Huacai Chen <chenhc(a)lemote.com>
Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
Cc: Huacai Chen <chenhc(a)lemote.com>
Cc: linux-mips(a)linux-mips.org
Cc: stable(a)vger.kernel.org # v4.4+
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index b2fa62922d88..49d6046ca1d0 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -13,6 +13,7 @@
#include <linux/atomic.h>
#include <linux/cpumask.h>
+#include <linux/sizes.h>
#include <linux/threads.h>
#include <asm/cachectl.h>
@@ -80,11 +81,10 @@ extern unsigned int vced_count, vcei_count;
#endif
-/*
- * One page above the stack is used for branch delay slot "emulation".
- * See dsemul.c for details.
- */
-#define STACK_TOP ((TASK_SIZE & PAGE_MASK) - PAGE_SIZE)
+#define VDSO_RANDOMIZE_SIZE (TASK_IS_32BIT_ADDR ? SZ_1M : SZ_256M)
+
+extern unsigned long mips_stack_top(void);
+#define STACK_TOP mips_stack_top()
/*
* This decides where the kernel will search for a free chunk of vm
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 8fc69891e117..d4f7fd4550e1 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -32,6 +32,7 @@
#include <linux/nmi.h>
#include <linux/cpu.h>
+#include <asm/abi.h>
#include <asm/asm.h>
#include <asm/bootinfo.h>
#include <asm/cpu.h>
@@ -39,6 +40,7 @@
#include <asm/dsp.h>
#include <asm/fpu.h>
#include <asm/irq.h>
+#include <asm/mips-cps.h>
#include <asm/msa.h>
#include <asm/pgtable.h>
#include <asm/mipsregs.h>
@@ -645,6 +647,29 @@ unsigned long get_wchan(struct task_struct *task)
return pc;
}
+unsigned long mips_stack_top(void)
+{
+ unsigned long top = TASK_SIZE & PAGE_MASK;
+
+ /* One page for branch delay slot "emulation" */
+ top -= PAGE_SIZE;
+
+ /* Space for the VDSO, data page & GIC user page */
+ top -= PAGE_ALIGN(current->thread.abi->vdso->size);
+ top -= PAGE_SIZE;
+ top -= mips_gic_present() ? PAGE_SIZE : 0;
+
+ /* Space for cache colour alignment */
+ if (cpu_has_dc_aliases)
+ top -= shm_align_mask + 1;
+
+ /* Space to randomize the VDSO base */
+ if (current->flags & PF_RANDOMIZE)
+ top -= VDSO_RANDOMIZE_SIZE;
+
+ return top;
+}
+
/*
* Don't forget that the stack pointer must be aligned on a 8 bytes
* boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index 8f845f6e5f42..48a9c6b90e07 100644
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -15,6 +15,7 @@
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/mm.h>
+#include <linux/random.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/timekeeper_internal.h>
@@ -97,6 +98,21 @@ void update_vsyscall_tz(void)
}
}
+static unsigned long vdso_base(void)
+{
+ unsigned long base;
+
+ /* Skip the delay slot emulation page */
+ base = STACK_TOP + PAGE_SIZE;
+
+ if (current->flags & PF_RANDOMIZE) {
+ base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
+ base = PAGE_ALIGN(base);
+ }
+
+ return base;
+}
+
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct mips_vdso_image *image = current->thread.abi->vdso;
@@ -137,7 +153,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
if (cpu_has_dc_aliases)
size += shm_align_mask + 1;
- base = get_unmapped_area(NULL, 0, size, 0, 0);
+ base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
if (IS_ERR_VALUE(base)) {
ret = base;
goto out;
I guess I should put more stable backport tags on stuff, I've been
bugged about not having requested a backport for the following:
commit 28e2c4bb99aa ("mm/vmstat.c: fix outdated vmstat_text"), for
stable kernels 4.14 and 4.18.
Unfortunately, it appears our fix in:
commit b5d29843d8ef ("drm/atomic_helper: Allow DPMS On<->Off changes
for unregistered connectors")
Which attempted to work around the problems introduced by:
commit 4d80273976bf ("drm/atomic_helper: Disallow new modesets on
unregistered connectors")
Is still not the right solution, as modesets can still be triggered
outside of drm_atomic_set_crtc_for_connector().
So in order to fix this, while still being careful that we don't break
modesets that a driver may perform before being registered with
userspace, we replace connector->registered with a tristate member,
connector->registration_state. This allows us to keep track of whether
or not a connector is still initializing and hasn't been exposed to
userspace, is currently registered and exposed to userspace, or has been
legitimately removed from the system after having once been present.
Using this info, we can prevent userspace from performing new modesets
on unregistered connectors while still allowing the driver to perform
modesets on unregistered connectors before the driver has finished being
registered.
Fixes: b5d29843d8ef ("drm/atomic_helper: Allow DPMS On<->Off changes for unregistered connectors")
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Cc: Daniel Vetter <daniel.vetter(a)ffwll.ch>
Cc: Rodrigo Vivi <rodrigo.vivi(a)intel.com>
Cc: stable(a)vger.kernel.org
Cc: David Airlie <airlied(a)linux.ie>
Signed-off-by: Lyude Paul <lyude(a)redhat.com>
---
drivers/gpu/drm/drm_atomic_helper.c | 60 +++++++++++++++++++++----
drivers/gpu/drm/drm_atomic_uapi.c | 21 ---------
drivers/gpu/drm/drm_connector.c | 10 ++---
drivers/gpu/drm/i915/intel_dp_mst.c | 8 ++--
include/drm/drm_connector.h | 68 ++++++++++++++++++++++++++++-
5 files changed, 127 insertions(+), 40 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 6f66777dca4b..6cadeaf28ae4 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -529,6 +529,35 @@ mode_valid(struct drm_atomic_state *state)
return 0;
}
+static int
+unregistered_connector_check(struct drm_atomic_state *state,
+ struct drm_connector *connector,
+ struct drm_connector_state *old_conn_state,
+ struct drm_connector_state *new_conn_state)
+{
+ struct drm_crtc_state *crtc_state;
+ struct drm_crtc *crtc;
+
+ if (!drm_connector_unregistered(connector))
+ return 0;
+
+ crtc = new_conn_state->crtc;
+ if (!crtc)
+ return 0;
+
+ crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+ if (!crtc_state || !drm_atomic_crtc_needs_modeset(crtc_state))
+ return 0;
+
+ if (crtc_state->mode_changed) {
+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] can't change mode on unregistered connector\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
/**
* drm_atomic_helper_check_modeset - validate state object for modeset changes
* @dev: DRM device
@@ -684,18 +713,33 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
return ret;
}
- /*
- * Iterate over all connectors again, to make sure atomic_check()
- * has been called on them when a modeset is forced.
- */
for_each_oldnew_connector_in_state(state, connector, old_connector_state, new_connector_state, i) {
const struct drm_connector_helper_funcs *funcs = connector->helper_private;
- if (connectors_mask & BIT(i))
- continue;
+ /* Make sure atomic_check() is called on any unchecked
+ * connectors when a modeset has been forced
+ */
+ if (connectors_mask & BIT(i) && funcs->atomic_check) {
+ ret = funcs->atomic_check(connector,
+ new_connector_state);
+ if (ret)
+ return ret;
+ }
- if (funcs->atomic_check)
- ret = funcs->atomic_check(connector, new_connector_state);
+ /*
+ * Prevent userspace from turning on new displays or setting
+ * new modes using connectors which have been removed from
+ * userspace. This is racy since an unplug could happen at any
+ * time including after this check, but that's OK: we only
+ * care about preventing userspace from trying to set invalid
+ * state using destroyed connectors that it's been notified
+ * about. No one can save us after the atomic check completes
+ * but ourselves.
+ */
+ ret = unregistered_connector_check(state,
+ connector,
+ old_connector_state,
+ new_connector_state);
if (ret)
return ret;
}
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index a22d6f269b07..d5b7f315098c 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -299,27 +299,6 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
struct drm_connector *connector = conn_state->connector;
struct drm_crtc_state *crtc_state;
- /*
- * For compatibility with legacy users, we want to make sure that
- * we allow DPMS On<->Off modesets on unregistered connectors, since
- * legacy modesetting users will not be expecting these to fail. We do
- * not however, want to allow legacy users to assign a connector
- * that's been unregistered from sysfs to another CRTC, since doing
- * this with a now non-existent connector could potentially leave us
- * in an invalid state.
- *
- * Since the connector can be unregistered at any point during an
- * atomic check or commit, this is racy. But that's OK: all we care
- * about is ensuring that userspace can't use this connector for new
- * configurations after it's been notified that the connector is no
- * longer present.
- */
- if (!READ_ONCE(connector->registered) && crtc) {
- DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] is not registered\n",
- connector->base.id, connector->name);
- return -EINVAL;
- }
-
if (conn_state->crtc == crtc)
return 0;
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 5d01414ec9f7..79943102fe18 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -396,7 +396,7 @@ void drm_connector_cleanup(struct drm_connector *connector)
/* The connector should have been removed from userspace long before
* it is finally destroyed.
*/
- if (WARN_ON(connector->registered))
+ if (WARN_ON(!drm_connector_unregistered(connector)))
drm_connector_unregister(connector);
if (connector->tile_group) {
@@ -453,7 +453,7 @@ int drm_connector_register(struct drm_connector *connector)
return 0;
mutex_lock(&connector->mutex);
- if (connector->registered)
+ if (connector->registration_state != DRM_CONNECTOR_INITIALIZING)
goto unlock;
ret = drm_sysfs_connector_add(connector);
@@ -473,7 +473,7 @@ int drm_connector_register(struct drm_connector *connector)
drm_mode_object_register(connector->dev, &connector->base);
- connector->registered = true;
+ connector->registration_state = DRM_CONNECTOR_REGISTERED;
goto unlock;
err_debugfs:
@@ -495,7 +495,7 @@ EXPORT_SYMBOL(drm_connector_register);
void drm_connector_unregister(struct drm_connector *connector)
{
mutex_lock(&connector->mutex);
- if (!connector->registered) {
+ if (connector->registration_state != DRM_CONNECTOR_REGISTERED) {
mutex_unlock(&connector->mutex);
return;
}
@@ -506,7 +506,7 @@ void drm_connector_unregister(struct drm_connector *connector)
drm_sysfs_connector_remove(connector);
drm_debugfs_connector_remove(connector);
- connector->registered = false;
+ connector->registration_state = DRM_CONNECTOR_UNREGISTERED;
mutex_unlock(&connector->mutex);
}
EXPORT_SYMBOL(drm_connector_unregister);
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index b268bdd71bd3..ad367309e10b 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -78,7 +78,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
pipe_config->pbn = mst_pbn;
/* Zombie connectors can't have VCPI slots */
- if (READ_ONCE(connector->registered)) {
+ if (!drm_connector_unregistered(connector)) {
slots = drm_dp_atomic_find_vcpi_slots(state,
&intel_dp->mst_mgr,
port,
@@ -314,7 +314,7 @@ static int intel_dp_mst_get_ddc_modes(struct drm_connector *connector)
struct edid *edid;
int ret;
- if (!READ_ONCE(connector->registered))
+ if (drm_connector_unregistered(connector))
return intel_connector_update_modes(connector, NULL);
edid = drm_dp_mst_get_edid(connector, &intel_dp->mst_mgr, intel_connector->port);
@@ -330,7 +330,7 @@ intel_dp_mst_detect(struct drm_connector *connector, bool force)
struct intel_connector *intel_connector = to_intel_connector(connector);
struct intel_dp *intel_dp = intel_connector->mst_port;
- if (!READ_ONCE(connector->registered))
+ if (drm_connector_unregistered(connector))
return connector_status_disconnected;
return drm_dp_mst_detect_port(connector, &intel_dp->mst_mgr,
intel_connector->port);
@@ -361,7 +361,7 @@ intel_dp_mst_mode_valid(struct drm_connector *connector,
int bpp = 24; /* MST uses fixed bpp */
int max_rate, mode_rate, max_lanes, max_link_clock;
- if (!READ_ONCE(connector->registered))
+ if (drm_connector_unregistered(connector))
return MODE_ERROR;
if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 5b3cf909fd5e..5f3e4a37bcd2 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -82,6 +82,51 @@ enum drm_connector_status {
connector_status_unknown = 3,
};
+/**
+ * enum drm_connector_registration_status - userspace registration status for
+ * a &drm_connector
+ *
+ * This enum is used to track the status of initializing a connector and
+ * registering it with userspace, so that DRM can prevent bogus modesets on
+ * connectors that no longer exist.
+ */
+enum drm_connector_registration_state {
+ /**
+ * @DRM_CONNECTOR_INITIALIZING: The connector has just been created,
+ * but has yet to be exposed to userspace. There should be no
+ * additional restrictions to how the state of this connector may be
+ * modified. connector to a new CRTC.
+ */
+ DRM_CONNECTOR_INITIALIZING = 0,
+
+ /**
+ * @DRM_CONNECTOR_REGISTERED: The connector has been fully initialized
+ * and registered with sysfs, as such it has been exposed to
+ * userspace. There should be no additional restrictions to how the
+ * state of this connector may be modified.
+ */
+ DRM_CONNECTOR_REGISTERED = 1,
+
+ /**
+ * @DRM_CONNECTOR_UNREGISTERED: The connector has either been exposed
+ * to userspace and has since been unregistered and removed from
+ * userspace, or the connector was destroyed before it had a chance to
+ * be exposed to userspace. There are additional restrictions to how
+ * the state of an unregistered connector may be modified:
+ *
+ * - The current display mode as exposed to userspace must remain the
+ * same as it was when the connector was unregistered.
+ * - The connector's currently assigned CRTC may be unassigned from
+ * this connector. Unassigning the connector's CRTC must be
+ * permanent.
+ * - New CRTCs must not be assigned to this connector.
+ * - The DPMS state of the connector (for compatibility with legacy
+ * modesetting) may modified freely, so long as doing so does not
+ * cause the new atomic state to violate any of these rules.
+ */
+ DRM_CONNECTOR_UNREGISTERED = 2,
+};
+
enum subpixel_order {
SubPixelUnknown = 0,
SubPixelHorizontalRGB,
@@ -853,10 +898,12 @@ struct drm_connector {
bool ycbcr_420_allowed;
/**
- * @registered: Is this connector exposed (registered) with userspace?
+ * @registration_state: Is this connector initializing, exposed
+ * (registered) with userspace, or unregistered?
+ *
* Protected by @mutex.
*/
- bool registered;
+ enum drm_connector_registration_state registration_state;
/**
* @modes:
@@ -1167,6 +1214,23 @@ static inline void drm_connector_unreference(struct drm_connector *connector)
drm_connector_put(connector);
}
+/**
+ * drm_connector_unregistered - has the connector been unregistered from
+ * userspace?
+ * @connector: DRM connector
+ *
+ * Checks whether or not @connector has been unregistered from userspace.
+ *
+ * Returns:
+ * True if the connector was unregistered, false if the connector is
+ * registered or has not yet been registered with userspace.
+ */
+static inline bool drm_connector_unregistered(struct drm_connector *connector)
+{
+ return READ_ONCE(connector->registration_state) ==
+ DRM_CONNECTOR_UNREGISTERED;
+}
+
const char *drm_get_connector_status_name(enum drm_connector_status status);
const char *drm_get_subpixel_order_name(enum subpixel_order order);
const char *drm_get_dpms_name(int val);
--
2.17.2
This is a note to let you know that I've just added the patch titled
USB: fix the usbfs flag sanitization for control transfers
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 665c365a77fbfeabe52694aedf3446d5f2f1ce42 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern(a)rowland.harvard.edu>
Date: Mon, 15 Oct 2018 16:55:04 -0400
Subject: USB: fix the usbfs flag sanitization for control transfers
Commit 7a68d9fb8510 ("USB: usbdevfs: sanitize flags more") checks the
transfer flags for URBs submitted from userspace via usbfs. However,
the check for whether the USBDEVFS_URB_SHORT_NOT_OK flag should be
allowed for a control transfer was added in the wrong place, before
the code has properly determined the direction of the control
transfer. (Control transfers are special because for them, the
direction is set by the bRequestType byte of the Setup packet rather
than direction bit of the endpoint address.)
This patch moves code which sets up the allow_short flag for control
transfers down after is_in has been set to the correct value.
Signed-off-by: Alan Stern <stern(a)rowland.harvard.edu>
Reported-and-tested-by: syzbot+24a30223a4b609bb802e(a)syzkaller.appspotmail.com
Fixes: 7a68d9fb8510 ("USB: usbdevfs: sanitize flags more")
CC: Oliver Neukum <oneukum(a)suse.com>
CC: <stable(a)vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/usb/core/devio.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 244417d0dfd1..ffccd40ea67d 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1474,8 +1474,6 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
u = 0;
switch (uurb->type) {
case USBDEVFS_URB_TYPE_CONTROL:
- if (is_in)
- allow_short = true;
if (!usb_endpoint_xfer_control(&ep->desc))
return -EINVAL;
/* min 8 byte setup packet */
@@ -1505,6 +1503,8 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
is_in = 0;
uurb->endpoint &= ~USB_DIR_IN;
}
+ if (is_in)
+ allow_short = true;
snoop(&ps->dev->dev, "control urb: bRequestType=%02x "
"bRequest=%02x wValue=%04x "
"wIndex=%04x wLength=%04x\n",
--
2.19.1
The patch titled
Subject: mm: /proc/pid/smaps_rollup: fix NULL pointer deref in smaps_pte_range()
has been added to the -mm tree. Its filename is
mm-proc-pid-smaps_rollup-fix-null-pointer-deref-in-smaps_pte_range.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-proc-pid-smaps_rollup-fix-null-…
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-proc-pid-smaps_rollup-fix-null-…
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 and is updated
there every 3-4 working days
------------------------------------------------------
From: Vlastimil Babka <vbabka(a)suse.cz>
Subject: mm: /proc/pid/smaps_rollup: fix NULL pointer deref in smaps_pte_range()
Leonardo reports an apparent regression in 4.19-rc7:
BUG: unable to handle kernel NULL pointer dereference at 00000000000000f0
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 3 PID: 6032 Comm: python Not tainted 4.19.0-041900rc7-lowlatency #201810071631
Hardware name: LENOVO 80UG/Toronto 4A2, BIOS 0XCN45WW 08/09/2018
RIP: 0010:smaps_pte_range+0x32d/0x540
Code: 80 00 00 00 00 74 a9 48 89 de 41 f6 40 52 40 0f 85 04 02 00 00 49 2b 30 48 c1 ee 0c 49 03 b0 98 00 00 00 49 8b 80 a0 00 00 00 <48> 8b b8 f0 00 00 00 e8 b7 ef ec ff 48 85 c0 0f 84 71 ff ff ff a8
RSP: 0018:ffffb0cbc484fb88 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000560ddb9e9000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000560ddb9e9 RDI: 0000000000000001
RBP: ffffb0cbc484fbc0 R08: ffff94a5a227a578 R09: ffff94a5a227a578
R10: 0000000000000000 R11: 0000560ddbbe7000 R12: ffffe903098ba728
R13: ffffb0cbc484fc78 R14: ffffb0cbc484fcf8 R15: ffff94a5a2e9cf48
FS: 00007f6dfb683740(0000) GS:ffff94a5aaf80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000f0 CR3: 000000011c118001 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__walk_page_range+0x3c2/0x6f0
walk_page_vma+0x42/0x60
smap_gather_stats+0x79/0xe0
? gather_pte_stats+0x320/0x320
? gather_hugetlb_stats+0x70/0x70
show_smaps_rollup+0xcd/0x1c0
seq_read+0x157/0x400
__vfs_read+0x3a/0x180
? security_file_permission+0x93/0xc0
? security_file_permission+0x93/0xc0
vfs_read+0x8f/0x140
ksys_read+0x55/0xc0
__x64_sys_read+0x1a/0x20
do_syscall_64+0x5a/0x110
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Decoded code matched to local compilation+disassembly points to
smaps_pte_entry():
} else if (unlikely(IS_ENABLED(CONFIG_SHMEM) && mss->check_shmem_swap
&& pte_none(*pte))) {
page = find_get_entry(vma->vm_file->f_mapping,
linear_page_index(vma, addr));
Here, vma->vm_file is NULL. mss->check_shmem_swap should be false in that
case, however for smaps_rollup, smap_gather_stats() can set the flag true
for one vma and leave it true for subsequent vma's where it should be
false.
To fix, reset the check_shmem_swap flag to false. There's also related
bug which sets mss->swap to shmem_swapped, which in the context of
smaps_rollup overwrites any value accumulated from previous vma's. Fix
that as well.
Note that the report suggests a regression between 4.17.19 and 4.19-rc7,
which makes the 4.19 series ending with commit 258f669e7e88 ("mm:
/proc/pid/smaps_rollup: convert to single value seq_file") suspicious.
But the mss was reused for rollup since 493b0e9d945f ("mm: add
/proc/pid/smaps_rollup") so let's play it safe with the stable backport.
Link: http://lkml.kernel.org/r/555fbd1f-4ac9-0b58-dcd4-5dc4380ff7ca@suse.cz
Link: https://bugzilla.kernel.org/show_bug.cgi?id=201377
Fixes: 493b0e9d945f ("mm: add /proc/pid/smaps_rollup")
Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz>
Reported-by: Leonardo Soares Mller <leozinho29_eu(a)hotmail.com>
Tested-by: Leonardo Soares Mller <leozinho29_eu(a)hotmail.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Daniel Colascione <dancol(a)google.com>
Cc: Alexey Dobriyan <adobriyan(a)gmail.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
fs/proc/task_mmu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/proc/task_mmu.c~mm-proc-pid-smaps_rollup-fix-null-pointer-deref-in-smaps_pte_range
+++ a/fs/proc/task_mmu.c
@@ -713,6 +713,8 @@ static void smap_gather_stats(struct vm_
smaps_walk.private = mss;
#ifdef CONFIG_SHMEM
+ /* In case of smaps_rollup, reset the value from previous vma */
+ mss->check_shmem_swap = false;
if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
/*
* For shared or readonly shmem mappings we know that all
@@ -728,7 +730,7 @@ static void smap_gather_stats(struct vm_
if (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
!(vma->vm_flags & VM_WRITE)) {
- mss->swap = shmem_swapped;
+ mss->swap += shmem_swapped;
} else {
mss->check_shmem_swap = true;
smaps_walk.pte_hole = smaps_pte_hole;
_
Patches currently in -mm which might be from vbabka(a)suse.cz are
mm-proc-pid-smaps_rollup-fix-null-pointer-deref-in-smaps_pte_range.patch
mm-slab-combine-kmalloc_caches-and-kmalloc_dma_caches.patch
mm-slab-slub-introduce-kmalloc-reclaimable-caches.patch
dcache-allocate-external-names-from-reclaimable-kmalloc-caches.patch
mm-rename-and-change-semantics-of-nr_indirectly_reclaimable_bytes.patch
mm-proc-add-kreclaimable-to-proc-meminfo.patch
mm-slab-shorten-kmalloc-cache-names-for-large-sizes.patch