[PATCH 4.9 0/9] 4.9.275-rc1 review

[PATCH 4.9 0/9] 4.9.275-rc1 review

[Greg Kroah-Hartman]

This is the start of the stable review cycle for the 4.9.275 release.
There are 9 patches in this series, all will be posted as a response
to this one.  If anyone has any issues with these being applied, please
let me know.

Responses should be made by Sun, 11 Jul 2021 13:14:09 +0000.
Anything received after that time might be too late.

The whole patch series can be found in one patch at:
	https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.275-rc1.gz
or in the git tree and branch at:
	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
and the diffstat can be found below.

thanks,

greg k-h

-------------
Pseudo-Shortlog of commits:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Linux 4.9.275-rc1

Juergen Gross <jgross@suse.com>
    xen/events: reset active flag for lateeoi events later

Petr Mladek <pmladek@suse.com>
    kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()

Petr Mladek <pmladek@suse.com>
    kthread_worker: split code for canceling the delayed work timer

Christian König <christian.koenig@amd.com>
    drm/nouveau: fix dma_address check for CPU/GPU sync

ManYi Li <limanyi@uniontech.com>
    scsi: sr: Return appropriate error code when disk is ejected

Hugh Dickins <hughd@google.com>
    mm, futex: fix shared futex pgoff on shmem huge page

Yang Shi <shy828301@gmail.com>
    mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split

Alex Shi <alex.shi@linux.alibaba.com>
    mm: add VM_WARN_ON_ONCE_PAGE() macro

Michal Hocko <mhocko@kernel.org>
    include/linux/mmdebug.h: make VM_WARN* non-rvals


-------------

Diffstat:

 Makefile                             |  4 +-
 drivers/gpu/drm/nouveau/nouveau_bo.c |  4 +-
 drivers/scsi/sr.c                    |  2 +
 drivers/xen/events/events_base.c     | 23 +++++++++--
 include/linux/hugetlb.h              | 15 -------
 include/linux/mmdebug.h              | 21 ++++++++--
 include/linux/pagemap.h              | 13 +++---
 kernel/futex.c                       |  2 +-
 kernel/kthread.c                     | 77 ++++++++++++++++++++++++------------
 mm/huge_memory.c                     | 29 +++++---------
 mm/hugetlb.c                         |  5 +--
 11 files changed, 112 insertions(+), 83 deletions(-)

[PATCH 4.9 1/9] include/linux/mmdebug.h: make VM_WARN* non-rvals

[Greg Kroah-Hartman]

From: Michal Hocko <mhocko@kernel.org>

[ Upstream commit 91241681c62a5a690c88eb2aca027f094125eaac ]

At present the construct

	if (VM_WARN(...))

will compile OK with CONFIG_DEBUG_VM=y and will fail with
CONFIG_DEBUG_VM=n.  The reason is that VM_{WARN,BUG}* have always been
special wrt.  {WARN/BUG}* and never generate any code when DEBUG_VM is
disabled.  So we cannot really use it in conditionals.

We considered changing things so that this construct works in both cases
but that might cause unwanted code generation with CONFIG_DEBUG_VM=n.
It is safer and simpler to make the build fail in both cases.

[akpm@linux-foundation.org: changelog]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/mmdebug.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 451a811f48f2..deaba1cc3cfc 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -36,10 +36,10 @@ void dump_mm(const struct mm_struct *mm);
 			BUG();						\
 		}							\
 	} while (0)
-#define VM_WARN_ON(cond) WARN_ON(cond)
-#define VM_WARN_ON_ONCE(cond) WARN_ON_ONCE(cond)
-#define VM_WARN_ONCE(cond, format...) WARN_ONCE(cond, format)
-#define VM_WARN(cond, format...) WARN(cond, format)
+#define VM_WARN_ON(cond) (void)WARN_ON(cond)
+#define VM_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
+#define VM_WARN_ONCE(cond, format...) (void)WARN_ONCE(cond, format)
+#define VM_WARN(cond, format...) (void)WARN(cond, format)
 #else
 #define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
 #define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)
-- 
2.30.2

[PATCH 4.9 2/9] mm: add VM_WARN_ON_ONCE_PAGE() macro

[Greg Kroah-Hartman]

From: Alex Shi <alex.shi@linux.alibaba.com>

[ Upstream commit a4055888629bc0467d12d912cd7c90acdf3d9b12 part ]

Add VM_WARN_ON_ONCE_PAGE() macro.

Link: https://lkml.kernel.org/r/1604283436-18880-3-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Note on stable backport: original commit was titled
mm/memcg: warning on !memcg after readahead page charged
which included uses of this macro in mm/memcontrol.c: here omitted.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/mmdebug.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index deaba1cc3cfc..d1fb3bbff37a 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -36,6 +36,18 @@ void dump_mm(const struct mm_struct *mm);
 			BUG();						\
 		}							\
 	} while (0)
+#define VM_WARN_ON_ONCE_PAGE(cond, page)	({			\
+	static bool __section(".data.once") __warned;			\
+	int __ret_warn_once = !!(cond);					\
+									\
+	if (unlikely(__ret_warn_once && !__warned)) {			\
+		dump_page(page, "VM_WARN_ON_ONCE_PAGE(" __stringify(cond)")");\
+		__warned = true;					\
+		WARN_ON(1);						\
+	}								\
+	unlikely(__ret_warn_once);					\
+})
+
 #define VM_WARN_ON(cond) (void)WARN_ON(cond)
 #define VM_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
 #define VM_WARN_ONCE(cond, format...) (void)WARN_ONCE(cond, format)
@@ -47,6 +59,7 @@ void dump_mm(const struct mm_struct *mm);
 #define VM_BUG_ON_MM(cond, mm) VM_BUG_ON(cond)
 #define VM_WARN_ON(cond) BUILD_BUG_ON_INVALID(cond)
 #define VM_WARN_ON_ONCE(cond) BUILD_BUG_ON_INVALID(cond)
+#define VM_WARN_ON_ONCE_PAGE(cond, page)  BUILD_BUG_ON_INVALID(cond)
 #define VM_WARN_ONCE(cond, format...) BUILD_BUG_ON_INVALID(cond)
 #define VM_WARN(cond, format...) BUILD_BUG_ON_INVALID(cond)
 #endif
-- 
2.30.2

[PATCH 4.9 3/9] mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split

[Greg Kroah-Hartman]

From: Yang Shi <shy828301@gmail.com>

[ Upstream commit 504e070dc08f757bccaed6d05c0f53ecbfac8a23 ]

When debugging the bug reported by Wang Yugui [1], try_to_unmap() may
fail, but the first VM_BUG_ON_PAGE() just checks page_mapcount() however
it may miss the failure when head page is unmapped but other subpage is
mapped.  Then the second DEBUG_VM BUG() that check total mapcount would
catch it.  This may incur some confusion.

As this is not a fatal issue, so consolidate the two DEBUG_VM checks
into one VM_WARN_ON_ONCE_PAGE().

[1] https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/

Link: https://lkml.kernel.org/r/d0f0db68-98b8-ebfb-16dc-f29df24cf012@google.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jue Wang <juew@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Note on stable backport: fixed up variables, split_queue_lock, tree_lock
in split_huge_page_to_list(); adapted to early version of unmap_page().

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 mm/huge_memory.c | 29 ++++++++++-------------------
 1 file changed, 10 insertions(+), 19 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 14cd0ef33b62..177ca028b986 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1891,7 +1891,7 @@ static void unmap_page(struct page *page)
 {
 	enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS |
 		TTU_RMAP_LOCKED;
-	int i, ret;
+	int i;
 
 	VM_BUG_ON_PAGE(!PageHead(page), page);
 
@@ -1899,15 +1899,16 @@ static void unmap_page(struct page *page)
 		ttu_flags |= TTU_MIGRATION;
 
 	/* We only need TTU_SPLIT_HUGE_PMD once */
-	ret = try_to_unmap(page, ttu_flags | TTU_SPLIT_HUGE_PMD);
-	for (i = 1; !ret && i < HPAGE_PMD_NR; i++) {
+	try_to_unmap(page, ttu_flags | TTU_SPLIT_HUGE_PMD);
+	for (i = 1; i < HPAGE_PMD_NR; i++) {
 		/* Cut short if the page is unmapped */
 		if (page_count(page) == 1)
 			return;
 
-		ret = try_to_unmap(page + i, ttu_flags);
+		try_to_unmap(page + i, ttu_flags);
 	}
-	VM_BUG_ON_PAGE(ret, page + i - 1);
+
+	VM_WARN_ON_ONCE_PAGE(page_mapped(page), page);
 }
 
 static void remap_page(struct page *page)
@@ -2137,7 +2138,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 	struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
 	struct anon_vma *anon_vma = NULL;
 	struct address_space *mapping = NULL;
-	int count, mapcount, extra_pins, ret;
+	int extra_pins, ret;
 	bool mlocked;
 	unsigned long flags;
 	pgoff_t end;
@@ -2200,7 +2201,6 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 
 	mlocked = PageMlocked(page);
 	unmap_page(head);
-	VM_BUG_ON_PAGE(compound_mapcount(head), head);
 
 	/* Make sure the page is not on per-CPU pagevec as it takes pin */
 	if (mlocked)
@@ -2226,9 +2226,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 
 	/* Prevent deferred_split_scan() touching ->_refcount */
 	spin_lock(&pgdata->split_queue_lock);
-	count = page_count(head);
-	mapcount = total_mapcount(head);
-	if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) {
+	if (page_ref_freeze(head, 1 + extra_pins)) {
 		if (!list_empty(page_deferred_list(head))) {
 			pgdata->split_queue_len--;
 			list_del(page_deferred_list(head));
@@ -2239,16 +2237,9 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 		__split_huge_page(page, list, end, flags);
 		ret = 0;
 	} else {
-		if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
-			pr_alert("total_mapcount: %u, page_count(): %u\n",
-					mapcount, count);
-			if (PageTail(page))
-				dump_page(head, NULL);
-			dump_page(page, "total_mapcount(head) > 0");
-			BUG();
-		}
 		spin_unlock(&pgdata->split_queue_lock);
-fail:		if (mapping)
+fail:
+		if (mapping)
 			spin_unlock(&mapping->tree_lock);
 		spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
 		remap_page(head);
-- 
2.30.2

[PATCH 4.9 4/9] mm, futex: fix shared futex pgoff on shmem huge page

[Greg Kroah-Hartman]

From: Hugh Dickins <hughd@google.com>

[ Upstream commit fe19bd3dae3d15d2fbfdb3de8839a6ea0fe94264 ]

If more than one futex is placed on a shmem huge page, it can happen
that waking the second wakes the first instead, and leaves the second
waiting: the key's shared.pgoff is wrong.

When 3.11 commit 13d60f4b6ab5 ("futex: Take hugepages into account when
generating futex_key"), the only shared huge pages came from hugetlbfs,
and the code added to deal with its exceptional page->index was put into
hugetlb source.  Then that was missed when 4.8 added shmem huge pages.

page_to_pgoff() is what others use for this nowadays: except that, as
currently written, it gives the right answer on hugetlbfs head, but
nonsense on hugetlbfs tails.  Fix that by calling hugetlbfs-specific
hugetlb_basepage_index() on PageHuge tails as well as on head.

Yes, it's unconventional to declare hugetlb_basepage_index() there in
pagemap.h, rather than in hugetlb.h; but I do not expect anything but
page_to_pgoff() ever to need it.

[akpm@linux-foundation.org: give hugetlb_basepage_index() prototype the correct scope]

Link: https://lkml.kernel.org/r/b17d946b-d09-326e-b42a-52884c36df32@google.com
Fixes: 800d8c63b2e9 ("shmem: add huge pages support")
Reported-by: Neel Natu <neelnatu@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Zhang Yi <wetpzy@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Note on stable backport: leave redundant #include <linux/hugetlb.h>
in kernel/futex.c, to avoid conflict over the header files included.
Resolved trivial conflicts in include/linux/hugetlb.h.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/hugetlb.h | 15 ---------------
 include/linux/pagemap.h | 13 +++++++------
 kernel/futex.c          |  2 +-
 mm/hugetlb.c            |  5 +----
 4 files changed, 9 insertions(+), 26 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 8dd365c65478..6417bc845db5 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -451,17 +451,6 @@ static inline int hstate_index(struct hstate *h)
 	return h - hstates;
 }
 
-pgoff_t __basepage_index(struct page *page);
-
-/* Return page->index in PAGE_SIZE units */
-static inline pgoff_t basepage_index(struct page *page)
-{
-	if (!PageCompound(page))
-		return page->index;
-
-	return __basepage_index(page);
-}
-
 extern int dissolve_free_huge_pages(unsigned long start_pfn,
 				    unsigned long end_pfn);
 static inline bool hugepage_migration_supported(struct hstate *h)
@@ -529,10 +518,6 @@ static inline unsigned int pages_per_huge_page(struct hstate *h)
 #define hstate_index_to_shift(index) 0
 #define hstate_index(h) 0
 
-static inline pgoff_t basepage_index(struct page *page)
-{
-	return page->index;
-}
 #define dissolve_free_huge_pages(s, e)	0
 #define hugepage_migration_supported(h)	false
 
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 35f4c4d9c405..8672291633dd 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -374,7 +374,7 @@ static inline struct page *read_mapping_page(struct address_space *mapping,
 }
 
 /*
- * Get index of the page with in radix-tree
+ * Get index of the page within radix-tree (but not for hugetlb pages).
  * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE)
  */
 static inline pgoff_t page_to_index(struct page *page)
@@ -393,15 +393,16 @@ static inline pgoff_t page_to_index(struct page *page)
 	return pgoff;
 }
 
+extern pgoff_t hugetlb_basepage_index(struct page *page);
+
 /*
- * Get the offset in PAGE_SIZE.
- * (TODO: hugepage should have ->index in PAGE_SIZE)
+ * Get the offset in PAGE_SIZE (even for hugetlb pages).
+ * (TODO: hugetlb pages should have ->index in PAGE_SIZE)
  */
 static inline pgoff_t page_to_pgoff(struct page *page)
 {
-	if (unlikely(PageHeadHuge(page)))
-		return page->index << compound_order(page);
-
+	if (unlikely(PageHuge(page)))
+		return hugetlb_basepage_index(page);
 	return page_to_index(page);
 }
 
diff --git a/kernel/futex.c b/kernel/futex.c
index 324fb85c8904..b3823736af6f 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -717,7 +717,7 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
 
 		key->both.offset |= FUT_OFF_INODE; /* inode-based key */
 		key->shared.i_seq = get_inode_sequence_number(inode);
-		key->shared.pgoff = basepage_index(tail);
+		key->shared.pgoff = page_to_pgoff(tail);
 		rcu_read_unlock();
 	}
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b7215b0807ca..de89e9295f6c 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1380,15 +1380,12 @@ int PageHeadHuge(struct page *page_head)
 	return get_compound_page_dtor(page_head) == free_huge_page;
 }
 
-pgoff_t __basepage_index(struct page *page)
+pgoff_t hugetlb_basepage_index(struct page *page)
 {
 	struct page *page_head = compound_head(page);
 	pgoff_t index = page_index(page_head);
 	unsigned long compound_idx;
 
-	if (!PageHuge(page_head))
-		return page_index(page);
-
 	if (compound_order(page_head) >= MAX_ORDER)
 		compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
 	else
-- 
2.30.2

[PATCH 4.9 5/9] scsi: sr: Return appropriate error code when disk is ejected

[Greg Kroah-Hartman]

From: ManYi Li <limanyi@uniontech.com>

[ Upstream commit 7dd753ca59d6c8cc09aa1ed24f7657524803c7f3 ]

Handle a reported media event code of 3. This indicates that the media has
been removed from the drive and user intervention is required to proceed.
Return DISK_EVENT_EJECT_REQUEST in that case.

Link: https://lore.kernel.org/r/20210611094402.23884-1-limanyi@uniontech.com
Signed-off-by: ManYi Li <limanyi@uniontech.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/sr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 67a73ea0a615..5e51a39a0c27 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -216,6 +216,8 @@ static unsigned int sr_get_events(struct scsi_device *sdev)
 		return DISK_EVENT_EJECT_REQUEST;
 	else if (med->media_event_code == 2)
 		return DISK_EVENT_MEDIA_CHANGE;
+	else if (med->media_event_code == 3)
+		return DISK_EVENT_EJECT_REQUEST;
 	return 0;
 }
 
-- 
2.30.2

[PATCH 4.9 6/9] drm/nouveau: fix dma_address check for CPU/GPU sync

[Greg Kroah-Hartman]

From: Christian König <christian.koenig@amd.com>

[ Upstream commit d330099115597bbc238d6758a4930e72b49ea9ba ]

AGP for example doesn't have a dma_address array.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210614110517.1624-1-christian.koenig@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/nouveau/nouveau_bo.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index a2e6a81669e7..94b7798bdea4 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -447,7 +447,7 @@ nouveau_bo_sync_for_device(struct nouveau_bo *nvbo)
 	struct ttm_dma_tt *ttm_dma = (struct ttm_dma_tt *)nvbo->bo.ttm;
 	int i;
 
-	if (!ttm_dma)
+	if (!ttm_dma || !ttm_dma->dma_address)
 		return;
 
 	/* Don't waste time looping if the object is coherent */
@@ -467,7 +467,7 @@ nouveau_bo_sync_for_cpu(struct nouveau_bo *nvbo)
 	struct ttm_dma_tt *ttm_dma = (struct ttm_dma_tt *)nvbo->bo.ttm;
 	int i;
 
-	if (!ttm_dma)
+	if (!ttm_dma || !ttm_dma->dma_address)
 		return;
 
 	/* Don't waste time looping if the object is coherent */
-- 
2.30.2

[PATCH 4.9 7/9] kthread_worker: split code for canceling the delayed work timer

[Greg Kroah-Hartman]

From: Petr Mladek <pmladek@suse.com>

commit 34b3d5344719d14fd2185b2d9459b3abcb8cf9d8 upstream.

Patch series "kthread_worker: Fix race between kthread_mod_delayed_work()
and kthread_cancel_delayed_work_sync()".

This patchset fixes the race between kthread_mod_delayed_work() and
kthread_cancel_delayed_work_sync() including proper return value
handling.

This patch (of 2):

Simple code refactoring as a preparation step for fixing a race between
kthread_mod_delayed_work() and kthread_cancel_delayed_work_sync().

It does not modify the existing behavior.

Link: https://lkml.kernel.org/r/20210610133051.15337-2-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: <jenhaochen@google.com>
Cc: Martin Liu <liumartin@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/kthread.c |   46 +++++++++++++++++++++++++++++-----------------
 1 file changed, 29 insertions(+), 17 deletions(-)

--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -952,6 +952,33 @@ void kthread_flush_work(struct kthread_w
 EXPORT_SYMBOL_GPL(kthread_flush_work);
 
 /*
+ * Make sure that the timer is neither set nor running and could
+ * not manipulate the work list_head any longer.
+ *
+ * The function is called under worker->lock. The lock is temporary
+ * released but the timer can't be set again in the meantime.
+ */
+static void kthread_cancel_delayed_work_timer(struct kthread_work *work,
+					      unsigned long *flags)
+{
+	struct kthread_delayed_work *dwork =
+		container_of(work, struct kthread_delayed_work, work);
+	struct kthread_worker *worker = work->worker;
+
+	/*
+	 * del_timer_sync() must be called to make sure that the timer
+	 * callback is not running. The lock must be temporary released
+	 * to avoid a deadlock with the callback. In the meantime,
+	 * any queuing is blocked by setting the canceling counter.
+	 */
+	work->canceling++;
+	spin_unlock_irqrestore(&worker->lock, *flags);
+	del_timer_sync(&dwork->timer);
+	spin_lock_irqsave(&worker->lock, *flags);
+	work->canceling--;
+}
+
+/*
  * This function removes the work from the worker queue. Also it makes sure
  * that it won't get queued later via the delayed work's timer.
  *
@@ -965,23 +992,8 @@ static bool __kthread_cancel_work(struct
 				  unsigned long *flags)
 {
 	/* Try to cancel the timer if exists. */
-	if (is_dwork) {
-		struct kthread_delayed_work *dwork =
-			container_of(work, struct kthread_delayed_work, work);
-		struct kthread_worker *worker = work->worker;
-
-		/*
-		 * del_timer_sync() must be called to make sure that the timer
-		 * callback is not running. The lock must be temporary released
-		 * to avoid a deadlock with the callback. In the meantime,
-		 * any queuing is blocked by setting the canceling counter.
-		 */
-		work->canceling++;
-		spin_unlock_irqrestore(&worker->lock, *flags);
-		del_timer_sync(&dwork->timer);
-		spin_lock_irqsave(&worker->lock, *flags);
-		work->canceling--;
-	}
+	if (is_dwork)
+		kthread_cancel_delayed_work_timer(work, flags);
 
 	/*
 	 * Try to remove the work from a worker list. It might either

[PATCH 4.9 8/9] kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()

[Greg Kroah-Hartman]

From: Petr Mladek <pmladek@suse.com>

commit 5fa54346caf67b4b1b10b1f390316ae466da4d53 upstream.

The system might hang with the following backtrace:

	schedule+0x80/0x100
	schedule_timeout+0x48/0x138
	wait_for_common+0xa4/0x134
	wait_for_completion+0x1c/0x2c
	kthread_flush_work+0x114/0x1cc
	kthread_cancel_work_sync.llvm.16514401384283632983+0xe8/0x144
	kthread_cancel_delayed_work_sync+0x18/0x2c
	xxxx_pm_notify+0xb0/0xd8
	blocking_notifier_call_chain_robust+0x80/0x194
	pm_notifier_call_chain_robust+0x28/0x4c
	suspend_prepare+0x40/0x260
	enter_state+0x80/0x3f4
	pm_suspend+0x60/0xdc
	state_store+0x108/0x144
	kobj_attr_store+0x38/0x88
	sysfs_kf_write+0x64/0xc0
	kernfs_fop_write_iter+0x108/0x1d0
	vfs_write+0x2f4/0x368
	ksys_write+0x7c/0xec

It is caused by the following race between kthread_mod_delayed_work()
and kthread_cancel_delayed_work_sync():

CPU0				CPU1

Context: Thread A		Context: Thread B

kthread_mod_delayed_work()
  spin_lock()
  __kthread_cancel_work()
     spin_unlock()
     del_timer_sync()
				kthread_cancel_delayed_work_sync()
				  spin_lock()
				  __kthread_cancel_work()
				    spin_unlock()
				    del_timer_sync()
				    spin_lock()

				  work->canceling++
				  spin_unlock
     spin_lock()
   queue_delayed_work()
     // dwork is put into the worker->delayed_work_list

   spin_unlock()

				  kthread_flush_work()
     // flush_work is put at the tail of the dwork

				    wait_for_completion()

Context: IRQ

  kthread_delayed_work_timer_fn()
    spin_lock()
    list_del_init(&work->node);
    spin_unlock()

BANG: flush_work is not longer linked and will never get proceed.

The problem is that kthread_mod_delayed_work() checks work->canceling
flag before canceling the timer.

A simple solution is to (re)check work->canceling after
__kthread_cancel_work().  But then it is not clear what should be
returned when __kthread_cancel_work() removed the work from the queue
(list) and it can't queue it again with the new @delay.

The return value might be used for reference counting.  The caller has
to know whether a new work has been queued or an existing one was
replaced.

The proper solution is that kthread_mod_delayed_work() will remove the
work from the queue (list) _only_ when work->canceling is not set.  The
flag must be checked after the timer is stopped and the remaining
operations can be done under worker->lock.

Note that kthread_mod_delayed_work() could remove the timer and then
bail out.  It is fine.  The other canceling caller needs to cancel the
timer as well.  The important thing is that the queue (list)
manipulation is done atomically under worker->lock.

Link: https://lkml.kernel.org/r/20210610133051.15337-3-pmladek@suse.com
Fixes: 9a6b06c8d9a220860468a ("kthread: allow to modify delayed kthread work")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reported-by: Martin Liu <liumartin@google.com>
Cc: <jenhaochen@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/kthread.c |   35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -979,8 +979,11 @@ static void kthread_cancel_delayed_work_
 }
 
 /*
- * This function removes the work from the worker queue. Also it makes sure
- * that it won't get queued later via the delayed work's timer.
+ * This function removes the work from the worker queue.
+ *
+ * It is called under worker->lock. The caller must make sure that
+ * the timer used by delayed work is not running, e.g. by calling
+ * kthread_cancel_delayed_work_timer().
  *
  * The work might still be in use when this function finishes. See the
  * current_work proceed by the worker.
@@ -988,13 +991,8 @@ static void kthread_cancel_delayed_work_
  * Return: %true if @work was pending and successfully canceled,
  *	%false if @work was not pending
  */
-static bool __kthread_cancel_work(struct kthread_work *work, bool is_dwork,
-				  unsigned long *flags)
+static bool __kthread_cancel_work(struct kthread_work *work)
 {
-	/* Try to cancel the timer if exists. */
-	if (is_dwork)
-		kthread_cancel_delayed_work_timer(work, flags);
-
 	/*
 	 * Try to remove the work from a worker list. It might either
 	 * be from worker->work_list or from worker->delayed_work_list.
@@ -1047,11 +1045,23 @@ bool kthread_mod_delayed_work(struct kth
 	/* Work must not be used with >1 worker, see kthread_queue_work() */
 	WARN_ON_ONCE(work->worker != worker);
 
-	/* Do not fight with another command that is canceling this work. */
+	/*
+	 * Temporary cancel the work but do not fight with another command
+	 * that is canceling the work as well.
+	 *
+	 * It is a bit tricky because of possible races with another
+	 * mod_delayed_work() and cancel_delayed_work() callers.
+	 *
+	 * The timer must be canceled first because worker->lock is released
+	 * when doing so. But the work can be removed from the queue (list)
+	 * only when it can be queued again so that the return value can
+	 * be used for reference counting.
+	 */
+	kthread_cancel_delayed_work_timer(work, &flags);
 	if (work->canceling)
 		goto out;
+	ret = __kthread_cancel_work(work);
 
-	ret = __kthread_cancel_work(work, true, &flags);
 fast_queue:
 	__kthread_queue_delayed_work(worker, dwork, delay);
 out:
@@ -1073,7 +1083,10 @@ static bool __kthread_cancel_work_sync(s
 	/* Work must not be used with >1 worker, see kthread_queue_work(). */
 	WARN_ON_ONCE(work->worker != worker);
 
-	ret = __kthread_cancel_work(work, is_dwork, &flags);
+	if (is_dwork)
+		kthread_cancel_delayed_work_timer(work, &flags);
+
+	ret = __kthread_cancel_work(work);
 
 	if (worker->current_work != work)
 		goto out_fast;

[PATCH 4.9 9/9] xen/events: reset active flag for lateeoi events later

[Greg Kroah-Hartman]

From: Juergen Gross <jgross@suse.com>

commit 3de218ff39b9e3f0d453fe3154f12a174de44b25 upstream.

In order to avoid a race condition for user events when changing
cpu affinity reset the active flag only when EOI-ing the event.

This is working fine as all user events are lateeoi events. Note that
lateeoi_ack_mask_dynirq() is not modified as there is no explicit call
to xen_irq_lateeoi() expected later.

Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time")
Tested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/xen/events/events_base.c |   23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -533,6 +533,9 @@ static void xen_irq_lateeoi_locked(struc
 	}
 
 	info->eoi_time = 0;
+
+	/* is_active hasn't been reset yet, do it now. */
+	smp_store_release(&info->is_active, 0);
 	do_unmask(info, EVT_MASK_REASON_EOI_PENDING);
 }
 
@@ -1778,10 +1781,22 @@ static void lateeoi_ack_dynirq(struct ir
 	struct irq_info *info = info_for_irq(data->irq);
 	evtchn_port_t evtchn = info ? info->evtchn : 0;
 
-	if (VALID_EVTCHN(evtchn)) {
-		do_mask(info, EVT_MASK_REASON_EOI_PENDING);
-		ack_dynirq(data);
-	}
+	if (!VALID_EVTCHN(evtchn))
+		return;
+
+	do_mask(info, EVT_MASK_REASON_EOI_PENDING);
+
+	if (unlikely(irqd_is_setaffinity_pending(data)) &&
+	    likely(!irqd_irq_disabled(data))) {
+		do_mask(info, EVT_MASK_REASON_TEMPORARY);
+
+		clear_evtchn(evtchn);
+
+		irq_move_masked_irq(data);
+
+		do_unmask(info, EVT_MASK_REASON_TEMPORARY);
+	} else
+		clear_evtchn(evtchn);
 }
 
 static void lateeoi_mask_ack_dynirq(struct irq_data *data)

Re: [PATCH 4.9 0/9] 4.9.275-rc1 review

[Shuah Khan]

On 7/9/21 7:18 AM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.9.275 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sun, 11 Jul 2021 13:14:09 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.275-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h
> 

Compiled and booted on my test system. No dmesg regressions.

Tested-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

Re: [PATCH 4.9 0/9] 4.9.275-rc1 review

[Naresh Kamboju]

On Fri, 9 Jul 2021 at 18:48, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> This is the start of the stable review cycle for the 4.9.275 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Sun, 11 Jul 2021 13:14:09 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
>         https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.275-rc1.gz
> or in the git tree and branch at:
>         git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h

Results from Linaro’s test farm.
No regressions on arm64, arm, x86_64, and i386.

Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>

## Build
* kernel: 4.9.275-rc1
* git: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
* git branch: linux-4.9.y
* git commit: 972f4299f6ca84d948d7be286aeca2e200c4c62c
* git describe: v4.9.274-10-g972f4299f6ca
* test details:
https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-4.9.y/build/v4.9.274-10-g972f4299f6ca

## No regressions (compared to v4.9.274-7-g901e917fb1e9)

## No fixes (compared to v4.9.274-7-g901e917fb1e9)

## Test result summary
 total: 65597, pass: 51002, fail: 595, skip: 11784, xfail: 2216,

## Build Summary
* arm: 97 total, 97 passed, 0 failed
* arm64: 24 total, 24 passed, 0 failed
* dragonboard-410c: 1 total, 1 passed, 0 failed
* hi6220-hikey: 1 total, 1 passed, 0 failed
* i386: 14 total, 14 passed, 0 failed
* juno-r2: 1 total, 1 passed, 0 failed
* mips: 36 total, 36 passed, 0 failed
* sparc: 9 total, 9 passed, 0 failed
* x15: 1 total, 1 passed, 0 failed
* x86: 1 total, 1 passed, 0 failed
* x86_64: 14 total, 14 passed, 0 failed

## Test suites summary
* fwts
* igt-gpu-tools
* install-android-platform-tools-r2600
* kselftest-android
* kselftest-bpf
* kselftest-breakpoints
* kselftest-capabilities
* kselftest-cgroup
* kselftest-clone3
* kselftest-core
* kselftest-cpu-hotplug
* kselftest-cpufreq
* kselftest-drivers
* kselftest-efivarfs
* kselftest-filesystems
* kselftest-firmware
* kselftest-fpu
* kselftest-futex
* kselftest-gpio
* kselftest-intel_pstate
* kselftest-ipc
* kselftest-ir
* kselftest-kcmp
* kselftest-kexec
* kselftest-kvm
* kselftest-lib
* kselftest-livepatch
* kselftest-lkdtm
* kselftest-membarrier
* kselftest-memfd
* kselftest-memory-hotplug
* kselftest-mincore
* kselftest-mount
* kselftest-mqueue
* kselftest-net
* kselftest-netfilter
* kselftest-nsfs
* kselftest-openat2
* kselftest-pid_namespace
* kselftest-pidfd
* kselftest-proc
* kselftest-pstore
* kselftest-ptrace
* kselftest-rseq
* kselftest-rtc
* kselftest-seccomp
* kselftest-sigaltstack
* kselftest-size
* kselftest-splice
* kselftest-static_keys
* kselftest-sync
* kselftest-sysctl
* kselftest-timens
* kselftest-timers
* kselftest-tmpfs
* kselftest-tpm2
* kselftest-user
* kselftest-vm
* kselftest-x86
* kselftest-zram
* kvm-unit-tests
* libhugetlbfs
* linux-log-parser
* ltp-cap_bounds-tests
* ltp-commands-tests
* ltp-containers-tests
* ltp-controllers-tests
* ltp-cpuhotplug-tests
* ltp-crypto-tests
* ltp-cve-tests
* ltp-dio-tests
* ltp-fcntl-locktests-[
* ltp-fcntl-locktests-tests
* ltp-filecaps-tests
* ltp-fs-tests
* ltp-fs_bind-tests
* ltp-fs_perms_simple-tests
* ltp-fsx-tests
* ltp-hugetlb-tests
* ltp-io-tests
* ltp-ipc-tests
* ltp-math-tests
* ltp-mm-tests
* ltp-nptl-tests
* ltp-open-posix-tests
* ltp-pty-tests
* ltp-sched-tests
* ltp-securebits-tests
* ltp-syscalls-tests
* ltp-tracing-tests
* network-basic-tests
* packetdrill
* perf
* ssuite
* v4l2-compliance

--
Linaro LKFT
https://lkft.linaro.org

Re: [PATCH 4.9 0/9] 4.9.275-rc1 review

[Guenter Roeck]

On Fri, Jul 09, 2021 at 03:18:27PM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.9.275 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sun, 11 Jul 2021 13:14:09 +0000.
> Anything received after that time might be too late.
> 

Build results:
	total: 163 pass: 163 fail: 0
Qemu test results:
	total: 382 pass: 382 fail: 0

Tested-by: Guenter Roeck <linux@roeck-us.net>

Guenter

Re: [PATCH 4.9 0/9] 4.9.275-rc1 review

[Florian Fainelli]

On 7/9/2021 6:18 AM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.9.275 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sun, 11 Jul 2021 13:14:09 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.275-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h

On ARCH_BRCMSTB, using 32-bit and 64-bit ARM kernels:

Tested-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH 4.9 0/9] 4.9.275-rc1 review

[Florian Fainelli]

On 7/9/21 6:18 AM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.9.275 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sun, 11 Jul 2021 13:14:09 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.275-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h

On ARCH_BRCMSTB, using 32-bit and 64-bit ARM kernels:

Tested-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian