Hi
As this goes to the 4.9 series according to
https://www.kernel.org/doc/html/latest/networking/netdev-FAQ.html#q-are-all…
I'm sending it primarily to stable(a)v.k.o but Cc'ing Dave and Xin Long.
Could you please apply 99253eb750fd ("ipv6: check sk sk_type and
protocol early in ip_mroute_set/getsockopt") to the 4.9 stable series?
While 5e1859fbcc3c was done back in 3.8-rc1, 99253eb750fd from
4.11-rc1 was not backported to older stable series itself, where it is
needed as well.
Only checked if applicable without change in 4.9, but the fix should
probably go as well to the 4.4 and 3.16.
Regards,
Salvatore
A single 32-bit PSR2 training pattern field follows the sixteen element
array of PSR table entries in the VBT spec. But, we incorrectly define
this PSR2 field for each of the PSR table entries. As a result, the PSR1
training pattern duration for any panel_type != 0 will be parsed
incorrectly. Secondly, PSR2 training pattern durations for VBTs with bdb
version >= 226 will also be wrong.
Cc: Rodrigo Vivi <rodrigo.vivi(a)intel.com>
Cc: José Roberto de Souza <jose.souza(a)intel.com>
Cc: stable(a)vger.kernel.org
Cc: stable(a)vger.kernel.org #v5.2
Fixes: 88a0d9606aff ("drm/i915/vbt: Parse and use the new field with PSR2 TP2/3 wakeup time")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111088
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204183
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan(a)intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Reviewed-by: José Roberto de Souza <jose.souza(a)intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi(a)intel.com>
Tested-by: François Guerraz <kubrick(a)fgv6.net>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi(a)intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190717223451.2595-1-dhinaka…
(cherry picked from commit b5ea9c9337007d6e700280c8a60b4e10d070fb53)
---
drivers/gpu/drm/i915/intel_bios.c | 2 +-
drivers/gpu/drm/i915/intel_vbt_defs.h | 6 +++---
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 1dc8d03ff127..ee6fa75d65a2 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -762,7 +762,7 @@ parse_psr(struct drm_i915_private *dev_priv, const struct bdb_header *bdb)
}
if (bdb->version >= 226) {
- u32 wakeup_time = psr_table->psr2_tp2_tp3_wakeup_time;
+ u32 wakeup_time = psr->psr2_tp2_tp3_wakeup_time;
wakeup_time = (wakeup_time >> (2 * panel_type)) & 0x3;
switch (wakeup_time) {
diff --git a/drivers/gpu/drm/i915/intel_vbt_defs.h b/drivers/gpu/drm/i915/intel_vbt_defs.h
index fdbbb9a53804..796c070bbe6f 100644
--- a/drivers/gpu/drm/i915/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/intel_vbt_defs.h
@@ -772,13 +772,13 @@ struct psr_table {
/* TP wake up time in multiple of 100 */
u16 tp1_wakeup_time;
u16 tp2_tp3_wakeup_time;
-
- /* PSR2 TP2/TP3 wakeup time for 16 panels */
- u32 psr2_tp2_tp3_wakeup_time;
} __packed;
struct bdb_psr {
struct psr_table psr_table[16];
+
+ /* PSR2 TP2/TP3 wakeup time for 16 panels */
+ u32 psr2_tp2_tp3_wakeup_time;
} __packed;
/*
--
2.17.1
The patch titled
Subject: mm/memcontrol.c: fix use after free in mem_cgroup_iter()
has been added to the -mm tree. Its filename is
mm-memcontrol-fix-use-after-free-in-mem_cgroup_iter.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-fix-use-after-free-i…
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-fix-use-after-free-i…
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: Miles Chen <miles.chen(a)mediatek.com>
Subject: mm/memcontrol.c: fix use after free in mem_cgroup_iter()
This patch is sent to report an use after free in mem_cgroup_iter() after
merging commit be2657752e9e ("mm: memcg: fix use after free in
mem_cgroup_iter()").
I work with android kernel tree (4.9 & 4.14), and commit be2657752e9e
("mm: memcg: fix use after free in mem_cgroup_iter()") has been merged to
the trees. However, I can still observe use after free issues addressed
in the commit be2657752e9e. (on low-end devices, a few times this month)
backtrace:
css_tryget <- crash here
mem_cgroup_iter
shrink_node
shrink_zones
do_try_to_free_pages
try_to_free_pages
__perform_reclaim
__alloc_pages_direct_reclaim
__alloc_pages_slowpath
__alloc_pages_nodemask
To debug, I poisoned mem_cgroup before freeing it:
static void __mem_cgroup_free(struct mem_cgroup *memcg)
for_each_node(node)
free_mem_cgroup_per_node_info(memcg, node);
free_percpu(memcg->stat);
+ /* poison memcg before freeing it */
+ memset(memcg, 0x78, sizeof(struct mem_cgroup));
kfree(memcg);
}
The coredump shows the position=0xdbbc2a00 is freed.
(gdb) p/x ((struct mem_cgroup_per_node *)0xe5009e00)->iter[8]
$13 = {position = 0xdbbc2a00, generation = 0x2efd}
0xdbbc2a00: 0xdbbc2e00 0x00000000 0xdbbc2800 0x00000100
0xdbbc2a10: 0x00000200 0x78787878 0x00026218 0x00000000
0xdbbc2a20: 0xdcad6000 0x00000001 0x78787800 0x00000000
0xdbbc2a30: 0x78780000 0x00000000 0x0068fb84 0x78787878
0xdbbc2a40: 0x78787878 0x78787878 0x78787878 0xe3fa5cc0
0xdbbc2a50: 0x78787878 0x78787878 0x00000000 0x00000000
0xdbbc2a60: 0x00000000 0x00000000 0x00000000 0x00000000
0xdbbc2a70: 0x00000000 0x00000000 0x00000000 0x00000000
0xdbbc2a80: 0x00000000 0x00000000 0x00000000 0x00000000
0xdbbc2a90: 0x00000001 0x00000000 0x00000000 0x00100000
0xdbbc2aa0: 0x00000001 0xdbbc2ac8 0x00000000 0x00000000
0xdbbc2ab0: 0x00000000 0x00000000 0x00000000 0x00000000
0xdbbc2ac0: 0x00000000 0x00000000 0xe5b02618 0x00001000
0xdbbc2ad0: 0x00000000 0x78787878 0x78787878 0x78787878
0xdbbc2ae0: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2af0: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b00: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b10: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b20: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b30: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b40: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b50: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b60: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b70: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2b80: 0x78787878 0x78787878 0x00000000 0x78787878
0xdbbc2b90: 0x78787878 0x78787878 0x78787878 0x78787878
0xdbbc2ba0: 0x78787878 0x78787878 0x78787878 0x78787878
In the reclaim path, try_to_free_pages() does not setup
sc.target_mem_cgroup and sc is passed to do_try_to_free_pages(), ...,
shrink_node().
In mem_cgroup_iter(), root is set to root_mem_cgroup because
sc->target_mem_cgroup is NULL. It is possible to assign a memcg to
root_mem_cgroup.nodeinfo.iter in mem_cgroup_iter().
try_to_free_pages
struct scan_control sc = {...}, target_mem_cgroup is 0x0;
do_try_to_free_pages
shrink_zones
shrink_node
mem_cgroup *root = sc->target_mem_cgroup;
memcg = mem_cgroup_iter(root, NULL, &reclaim);
mem_cgroup_iter()
if (!root)
root = root_mem_cgroup;
...
css = css_next_descendant_pre(css, &root->css);
memcg = mem_cgroup_from_css(css);
cmpxchg(&iter->position, pos, memcg);
My device uses memcg non-hierarchical mode. When we release a memcg:
invalidate_reclaim_iterators() reaches only dead_memcg and its parents.
If non-hierarchical mode is used, invalidate_reclaim_iterators() never
reaches root_mem_cgroup.
static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
{
struct mem_cgroup *memcg = dead_memcg;
for (; memcg; memcg = parent_mem_cgroup(memcg)
...
}
So the use after free scenario looks like:
CPU1 CPU2
try_to_free_pages
do_try_to_free_pages
shrink_zones
shrink_node
mem_cgroup_iter()
if (!root)
root = root_mem_cgroup;
...
css = css_next_descendant_pre(css, &root->css);
memcg = mem_cgroup_from_css(css);
cmpxchg(&iter->position, pos, memcg);
invalidate_reclaim_iterators(memcg);
...
__mem_cgroup_free()
kfree(memcg);
try_to_free_pages
do_try_to_free_pages
shrink_zones
shrink_node
mem_cgroup_iter()
if (!root)
root = root_mem_cgroup;
...
mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id);
iter = &mz->iter[reclaim->priority];
pos = READ_ONCE(iter->position);
css_tryget(&pos->css) <- use after free
To avoid this, we should also invalidate root_mem_cgroup.nodeinfo.iter in
invalidate_reclaim_iterators().
Link: http://lkml.kernel.org/r/20190730015729.4406-1-miles.chen@mediatek.com
Fixes: 5ac8fb31ad2e ("mm: memcontrol: convert reclaim iterator to simple css refcounting")
Signed-off-by: Miles Chen <miles.chen(a)mediatek.com>
Acked-by: Michal Hocko <mhocko(a)suse.com>
Cc: Johannes Weiner <hannes(a)cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev(a)gmail.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/memcontrol.c | 39 +++++++++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 10 deletions(-)
--- a/mm/memcontrol.c~mm-memcontrol-fix-use-after-free-in-mem_cgroup_iter
+++ a/mm/memcontrol.c
@@ -1130,26 +1130,45 @@ void mem_cgroup_iter_break(struct mem_cg
css_put(&prev->css);
}
-static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
+ struct mem_cgroup *dead_memcg)
{
- struct mem_cgroup *memcg = dead_memcg;
struct mem_cgroup_reclaim_iter *iter;
struct mem_cgroup_per_node *mz;
int nid;
int i;
- for (; memcg; memcg = parent_mem_cgroup(memcg)) {
- for_each_node(nid) {
- mz = mem_cgroup_nodeinfo(memcg, nid);
- for (i = 0; i <= DEF_PRIORITY; i++) {
- iter = &mz->iter[i];
- cmpxchg(&iter->position,
- dead_memcg, NULL);
- }
+ for_each_node(nid) {
+ mz = mem_cgroup_nodeinfo(from, nid);
+ for (i = 0; i <= DEF_PRIORITY; i++) {
+ iter = &mz->iter[i];
+ cmpxchg(&iter->position,
+ dead_memcg, NULL);
}
}
}
+static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+{
+ struct mem_cgroup *memcg = dead_memcg;
+ struct mem_cgroup *last;
+
+ do {
+ __invalidate_reclaim_iterators(memcg, dead_memcg);
+ last = memcg;
+ } while (memcg = parent_mem_cgroup(memcg));
+
+ /*
+ * When cgruop1 non-hierarchy mode is used,
+ * parent_mem_cgroup() does not walk all the way up to the
+ * cgroup root (root_mem_cgroup). So we have to handle
+ * dead_memcg from cgroup root separately.
+ */
+ if (last != root_mem_cgroup)
+ __invalidate_reclaim_iterators(root_mem_cgroup,
+ dead_memcg);
+}
+
/**
* mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
* @memcg: hierarchy root
_
Patches currently in -mm which might be from miles.chen(a)mediatek.com are
mm-memcontrol-fix-use-after-free-in-mem_cgroup_iter.patch
Although SAS3 & SAS3.5 IT HBA controllers support
64-bit DMA addressing, as per hardware design,
if DMA able range contains all 64-bits set (0xFFFFFFFF-FFFFFFFF) then
it results in a firmware fault.
e.g. SGE's start address is 0xFFFFFFFF-FFFF000 and
data length is 0x1000 bytes. when HBA tries to DMA the data
at 0xFFFFFFFF-FFFFFFFF location then HBA will
fault the firmware.
Fix:
Driver will set 63-bit DMA mask to ensure the above address
will not be used.
Cc: <stable(a)vger.kernel.org> # 5.1.20+
Signed-off-by: Suganath Prabu <suganath-prabu.subramani(a)broadcom.com>
Reviewed-by: Christoph Hellwig <hch(a)lst.de>
---
V1 Change: Added tag for stable tree
V2 Change: Updated patch description.
drivers/scsi/mpt3sas/mpt3sas_base.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 6846628..050c0f0 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -2703,6 +2703,8 @@ _base_config_dma_addressing(struct MPT3SAS_ADAPTER *ioc, struct pci_dev *pdev)
{
u64 required_mask, coherent_mask;
struct sysinfo s;
+ /* Set 63 bit DMA mask for all SAS3 and SAS35 controllers */
+ int dma_mask = (ioc->hba_mpi_version_belonged > MPI2_VERSION) ? 63 : 64;
if (ioc->is_mcpu_endpoint)
goto try_32bit;
@@ -2712,17 +2714,17 @@ _base_config_dma_addressing(struct MPT3SAS_ADAPTER *ioc, struct pci_dev *pdev)
goto try_32bit;
if (ioc->dma_mask)
- coherent_mask = DMA_BIT_MASK(64);
+ coherent_mask = DMA_BIT_MASK(dma_mask);
else
coherent_mask = DMA_BIT_MASK(32);
- if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(64)) ||
+ if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(dma_mask)) ||
dma_set_coherent_mask(&pdev->dev, coherent_mask))
goto try_32bit;
ioc->base_add_sg_single = &_base_add_sg_single_64;
ioc->sge_size = sizeof(Mpi2SGESimple64_t);
- ioc->dma_mask = 64;
+ ioc->dma_mask = dma_mask;
goto out;
try_32bit:
@@ -2744,7 +2746,7 @@ static int
_base_change_consistent_dma_mask(struct MPT3SAS_ADAPTER *ioc,
struct pci_dev *pdev)
{
- if (pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64))) {
+ if (pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(ioc->dma_mask))) {
if (pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32)))
return -ENODEV;
}
@@ -4989,7 +4991,7 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc)
total_sz += sz;
} while (ioc->rdpq_array_enable && (++i < ioc->reply_queue_count));
- if (ioc->dma_mask == 64) {
+ if (ioc->dma_mask > 32) {
if (_base_change_consistent_dma_mask(ioc, ioc->pdev) != 0) {
ioc_warn(ioc, "no suitable consistent DMA mask for %s\n",
pci_name(ioc->pdev));
--
1.8.3.1
CLANG_FLAGS is initialized by the following line:
CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%))
..., which is run only when CROSS_COMPILE is set.
Some build targets (bindeb-pkg etc.) recurse to the top Makefile.
When you build the kernel with Clang but without CROSS_COMPILE,
the same compiler flags such as -no-integrated-as are accumulated
into CLANG_FLAGS.
If you run 'make CC=clang' and then 'make CC=clang bindeb-pkg',
Kbuild will recompile everything needlessly due to the build command
change.
Fix this by correctly initializing CLANG_FLAGS.
Fixes: 238bcbc4e07f ("kbuild: consolidate Clang compiler flags")
Cc: <stable(a)vger.kernel.org> # v4.20+
Signed-off-by: Masahiro Yamada <yamada.masahiro(a)socionext.com>
---
Makefile | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index fa0fbe7851ea..5ee6f6889869 100644
--- a/Makefile
+++ b/Makefile
@@ -472,6 +472,7 @@ KBUILD_CFLAGS_MODULE := -DMODULE
KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
KBUILD_LDFLAGS :=
GCC_PLUGINS_CFLAGS :=
+CLANG_FLAGS :=
export ARCH SRCARCH CONFIG_SHELL HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC
export CPP AR NM STRIP OBJCOPY OBJDUMP PAHOLE KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS
@@ -519,7 +520,7 @@ endif
ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
ifneq ($(CROSS_COMPILE),)
-CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%))
+CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)
GCC_TOOLCHAIN := $(realpath $(GCC_TOOLCHAIN_DIR)/..)
--
2.17.1
A build rule fails, the .DELETE_ON_ERROR special target removes the
target, but does nothing for the .*.cmd file, which might be corrupted.
So, .*.cmd files should be included only when the corresponding targets
exist.
Commit 392885ee82d3 ("kbuild: let fixdep directly write to .*.cmd
files") missed to fix up this file.
Fixes: 392885ee82d3 ("kbuild: let fixdep directly write to .*.cmd")
Cc: <stable(a)vger.kernel.org> # v5.0+
Signed-off-by: Masahiro Yamada <yamada.masahiro(a)socionext.com>
---
scripts/Makefile.modpost | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 6b19c1a4eae5..ad4b9829a456 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -145,10 +145,8 @@ FORCE:
# optimization, we don't need to read them if the target does not
# exist, we will rebuild anyway in that case.
-cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
+existing-targets := $(wildcard $(sort $(targets)))
-ifneq ($(cmd_files),)
- include $(cmd_files)
-endif
+-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
.PHONY: $(PHONY)
--
2.17.1
Now that -Wimplicit-fallthrough is passed to GCC by default, the
following warnings shows up:
../drivers/gpu/drm/arm/malidp_hw.c: In function ‘malidp_format_get_bpp’:
../drivers/gpu/drm/arm/malidp_hw.c:387:8: warning: this statement may fall
through [-Wimplicit-fallthrough=]
bpp = 30;
~~~~^~~~
../drivers/gpu/drm/arm/malidp_hw.c:388:3: note: here
case DRM_FORMAT_YUV420_10BIT:
^~~~
../drivers/gpu/drm/arm/malidp_hw.c: In function ‘malidp_se_irq’:
../drivers/gpu/drm/arm/malidp_hw.c:1311:4: warning: this statement may fall
through [-Wimplicit-fallthrough=]
drm_writeback_signal_completion(&malidp->mw_connector, 0);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/gpu/drm/arm/malidp_hw.c:1313:3: note: here
case MW_START:
^~~~
Rework to add a 'break;' in a case that didn't have it so that
the compiler doesn't warn about fall-through.
Cc: stable(a)vger.kernel.org # v5.2+
Fixes: b8207562abdd ("drm/arm/malidp: Specified the rotation memory requirements for AFBC YUV formats")
Acked-by: Liviu Dudau <liviu.dudau(a)arm.com>
Signed-off-by: Anders Roxell <anders.roxell(a)linaro.org>
---
drivers/gpu/drm/arm/malidp_hw.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/arm/malidp_hw.c b/drivers/gpu/drm/arm/malidp_hw.c
index 50af399d7f6f..380be66d4c6e 100644
--- a/drivers/gpu/drm/arm/malidp_hw.c
+++ b/drivers/gpu/drm/arm/malidp_hw.c
@@ -385,6 +385,7 @@ int malidp_format_get_bpp(u32 fmt)
switch (fmt) {
case DRM_FORMAT_VUY101010:
bpp = 30;
+ break;
case DRM_FORMAT_YUV420_10BIT:
bpp = 15;
break;
@@ -1309,7 +1310,7 @@ static irqreturn_t malidp_se_irq(int irq, void *arg)
break;
case MW_RESTART:
drm_writeback_signal_completion(&malidp->mw_connector, 0);
- /* fall through to a new start */
+ /* fall through - to a new start */
case MW_START:
/* writeback started, need to emulate one-shot mode */
hw->disable_memwrite(hwdev);
--
2.20.1
On Tue, Jul 30, 2019 at 7:52 PM Marek Marczykowski-Górecki
<marmarek(a)invisiblethingslab.com> wrote:
>
> On Tue, Jul 30, 2019 at 10:05:42AM -0400, Boris Ostrovsky wrote:
> > On 7/30/19 2:03 AM, Souptick Joarder wrote:
> > > On Mon, Jul 29, 2019 at 7:06 PM Marek Marczykowski-Górecki
> > > <marmarek(a)invisiblethingslab.com> wrote:
> > >> On Mon, Jul 29, 2019 at 02:02:54PM +0530, Souptick Joarder wrote:
> > >>> On Mon, Jul 29, 2019 at 1:35 PM Souptick Joarder <jrdr.linux(a)gmail.com> wrote:
> > >>>> On Sun, Jul 28, 2019 at 11:36 PM Marek Marczykowski-Górecki
> > >>>> <marmarek(a)invisiblethingslab.com> wrote:
> > >>>>> On Fri, Feb 15, 2019 at 08:18:31AM +0530, Souptick Joarder wrote:
> > >>>>>> Convert to use vm_map_pages() to map range of kernel
> > >>>>>> memory to user vma.
> > >>>>>>
> > >>>>>> map->count is passed to vm_map_pages() and internal API
> > >>>>>> verify map->count against count ( count = vma_pages(vma))
> > >>>>>> for page array boundary overrun condition.
> > >>>>> This commit breaks gntdev driver. If vma->vm_pgoff > 0, vm_map_pages
> > >>>>> will:
> > >>>>> - use map->pages starting at vma->vm_pgoff instead of 0
> > >>>> The actual code ignores vma->vm_pgoff > 0 scenario and mapped
> > >>>> the entire map->pages[i]. Why the entire map->pages[i] needs to be mapped
> > >>>> if vma->vm_pgoff > 0 (in original code) ?
> > >> vma->vm_pgoff is used as index passed to gntdev_find_map_index. It's
> > >> basically (ab)using this parameter for "which grant reference to map".
> > >>
> > >>>> are you referring to set vma->vm_pgoff = 0 irrespective of value passed
> > >>>> from user space ? If yes, using vm_map_pages_zero() is an alternate
> > >>>> option.
> > >> Yes, that should work.
> > > I prefer to use vm_map_pages_zero() to resolve both the issues. Alternatively
> > > the patch can be reverted as you suggested. Let me know you opinion and wait
> > > for feedback from others.
> > >
> > > Boris, would you like to give any feedback ?
> >
> > vm_map_pages_zero() looks good to me. Marek, does it work for you?
>
> Yes, replacing vm_map_pages() with vm_map_pages_zero() fixes the
> problem for me.
Marek, I can send a patch for the same if you are ok.
We need to cc stable as this changes are available in 5.2.4.
>
> --
> Best Regards,
> Marek Marczykowski-Górecki
> Invisible Things Lab
> A: Because it messes up the order in which people normally read text.
> Q: Why is top-posting such a bad thing?