diff --git a/patches.backports/memcg-null-ptr.patch b/patches.backports/memcg-null-ptr.patch deleted file mode 100644 index 319ac52..0000000 --- a/patches.backports/memcg-null-ptr.patch +++ /dev/null @@ -1,78 +0,0 @@ -From: Michal Hocko -Subject: mm: workingset: fix NULL ptr in count_shadow_nodes - -0a6b76dd23fa ("mm: workingset: make shadow node shrinker memcg aware") -has made the workingset shadow nodes shrinker memcg aware. The -implementation is not correct though because memcg_kmem_enabled() might -become true while we are doing a global reclaim when the sc->memcg might -be NULL which is exactly what Marek has seen: - -[ 15.665196] BUG: unable to handle kernel NULL pointer dereference at 0000000000000400 -[ 15.665213] IP: [] mem_cgroup_node_nr_lru_pages+0x20/0x40 -[ 15.665225] PGD 0 -[ 15.665230] Oops: 0000 [#1] SMP -[ 15.665285] CPU: 0 PID: 60 Comm: kswapd0 Tainted: G O 4.8.10-12.pvops.qubes.x86_64 #1 -[ 15.665292] task: ffff880011863b00 task.stack: ffff880011868000 -[ 15.665297] RIP: e030:[] [] mem_cgroup_node_nr_lru_pages+0x20/0x40 -[ 15.665307] RSP: e02b:ffff88001186bc70 EFLAGS: 00010293 -[ 15.665311] RAX: 0000000000000000 RBX: ffff88001186bd20 RCX: 0000000000000002 -[ 15.665317] RDX: 000000000000000c RSI: 0000000000000000 RDI: 0000000000000000 -[ 15.665322] RBP: ffff88001186bc70 R08: 28f5c28f5c28f5c3 R09: 0000000000000000 -[ 15.665327] R10: 0000000000006c34 R11: 0000000000000333 R12: 00000000000001f6 -[ 15.665332] R13: ffffffff81c6f6a0 R14: 0000000000000000 R15: 0000000000000000 -[ 15.665343] FS: 0000000000000000(0000) GS:ffff880013c00000(0000) knlGS:ffff880013d00000 -[ 15.665351] CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033 -[ 15.665358] CR2: 0000000000000400 CR3: 00000000122f2000 CR4: 0000000000042660 -[ 15.665366] Stack: -[ 15.665371] ffff88001186bc98 ffffffff811e0dda 00000000000002eb 0000000000000080 -[ 15.665384] ffffffff81c6f6a0 ffff88001186bd70 ffffffff811c36d9 0000000000000000 -[ 15.665397] ffff88001186bcb0 ffff88001186bcb0 ffff88001186bcc0 000000000000abc5 -[ 15.665410] Call Trace: -[ 15.665419] [] count_shadow_nodes+0x9a/0xa0 -[ 15.665428] [] shrink_slab.part.42+0x119/0x3e0 -[ 15.666049] [] shrink_node+0x22c/0x320 -[ 15.666049] [] kswapd+0x32c/0x700 -[ 15.666049] [] ? mem_cgroup_shrink_node+0x180/0x180 -[ 15.666049] [] kthread+0xd8/0xf0 -[ 15.666049] [] ret_from_fork+0x1f/0x40 -[ 15.666049] [] ? kthread_create_on_node+0x190/0x190 -[ 15.666049] Code: 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 3b 35 dd eb b1 00 55 48 89 e5 73 2c 89 d2 31 c9 31 c0 4c 63 ce 48 0f a3 ca 73 13 <4a> 8b b4 cf 00 04 00 00 41 89 c8 4a 03 84 c6 80 00 00 00 83 c1 -[ 15.666049] RIP [] mem_cgroup_node_nr_lru_pages+0x20/0x40 -[ 15.666049] RSP -[ 15.666049] CR2: 0000000000000400 -[ 15.666049] ---[ end trace 100494b9edbdfc4d ]--- - -This patch fixes the issue by checking sc->memcg rather than -memcg_kmem_enabled() which is sufficient because shrink_slab makes sure -that only memcg aware shrinkers will get non-NULL memcgs and only if -memcg_kmem_enabled is true. - -Fixes: 0a6b76dd23fa ("mm: workingset: make shadow node shrinker memcg aware") -Link: http://lkml.kernel.org/r/20161201132156.21450-1-mhocko@kernel.org -Signed-off-by: Michal Hocko -Reported-by: Marek Marczykowski-Górecki -Tested-by: Marek Marczykowski-Górecki -Acked-by: Vladimir Davydov -Acked-by: Johannes Weiner -Acked-by: Balbir Singh -Cc: [4.6+] -Signed-off-by: Andrew Morton ---- - - mm/workingset.c | 2 +- - 1 file changed, 1 insertion(+), 1 deletion(-) - -diff -puN mm/workingset.c~mm-workingset-fix-null-ptr-in-count_shadow_nodes mm/workingset.c ---- a/mm/workingset.c~mm-workingset-fix-null-ptr-in-count_shadow_nodes -+++ a/mm/workingset.c -@@ -348,7 +348,7 @@ static unsigned long count_shadow_nodes( - shadow_nodes = list_lru_shrink_count(&workingset_shadow_nodes, sc); - local_irq_enable(); - -- if (memcg_kmem_enabled()) { -+ if (sc->memcg) { - pages = mem_cgroup_node_nr_lru_pages(sc->memcg, sc->nid, - LRU_ALL_FILE); - } else { -_ - diff --git a/series.conf b/series.conf index 528f6e4..0950b46 100644 --- a/series.conf +++ b/series.conf @@ -5,9 +5,6 @@ patches.xen/xen-netfront-detach-crash.patch patches.xen/0001-mce-hide-EBUSY-initialization-error-on-Xen.patch patches.xen/irq-bind-debug-log.patch -# Backports -patches.backports/memcg-null-ptr.patch - # Additional features #patches.xen/pvops-0100-usb-xen-pvusb-driver.patch patches.xen/pvops-blkfront-removable-flag.patch @@ -25,4 +22,3 @@ patches.xen/xsa155-linux44-0013-xen-blkfront-prepare-request-locally-only-then-p # MSI-X enabled device passthrough fix (#1734) patches.xen/pci_op-cleanup.patch -