linux/kernel/power
James Morse 924d869675 PM / hibernate: Fix rtree_next_node() to avoid walking off list ends
rtree_next_node() walks the linked list of leaf nodes to find the next
block of pages in the struct memory_bitmap. If it walks off the end of
the list of nodes, it walks the list of memory zones to find the next
region of memory. If it walks off the end of the list of zones, it
returns false.

This leaves the struct bm_position's node and zone pointers pointing
at their respective struct list_heads in struct mem_zone_bm_rtree.

memory_bm_find_bit() uses struct bm_position's node and zone pointers
to avoid walking lists and trees if the next bit appears in the same
node/zone. It handles these values being stale.

Swap rtree_next_node()s 'step then test' to 'test-next then step',
this means if we reach the end of memory we return false and leave
the node and zone pointers as they were.

This fixes a panic on resume using AMD Seattle with 64K pages:
[    6.868732] Freezing user space processes ... (elapsed 0.000 seconds) done.
[    6.875753] Double checking all user space processes after OOM killer disable... (elapsed 0.000 seconds)
[    6.896453] PM: Using 3 thread(s) for decompression.
[    6.896453] PM: Loading and decompressing image data (5339 pages)...
[    7.318890] PM: Image loading progress:   0%
[    7.323395] Unable to handle kernel paging request at virtual address 00800040
[    7.330611] pgd = ffff000008df0000
[    7.334003] [00800040] *pgd=00000083fffe0003, *pud=00000083fffe0003, *pmd=00000083fffd0003, *pte=0000000000000000
[    7.344266] Internal error: Oops: 96000005 [#1] PREEMPT SMP
[    7.349825] Modules linked in:
[    7.352871] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G        W I     4.8.0-rc1 #4737
[    7.360512] Hardware name: AMD Overdrive/Supercharger/Default string, BIOS ROD1002C 04/08/2016
[    7.369109] task: ffff8003c0220000 task.stack: ffff8003c0280000
[    7.375020] PC is at set_bit+0x18/0x30
[    7.378758] LR is at memory_bm_set_bit+0x24/0x30
[    7.383362] pc : [<ffff00000835bbc8>] lr : [<ffff0000080faf18>] pstate: 60000045
[    7.390743] sp : ffff8003c0283b00
[    7.473551]
[    7.475031] Process swapper/0 (pid: 1, stack limit = 0xffff8003c0280020)
[    7.481718] Stack: (0xffff8003c0283b00 to 0xffff8003c0284000)
[    7.800075] Call trace:
[    7.887097] [<ffff00000835bbc8>] set_bit+0x18/0x30
[    7.891876] [<ffff0000080fb038>] duplicate_memory_bitmap.constprop.38+0x54/0x70
[    7.899172] [<ffff0000080fcc40>] snapshot_write_next+0x22c/0x47c
[    7.905166] [<ffff0000080fe1b4>] load_image_lzo+0x754/0xa88
[    7.910725] [<ffff0000080ff0a8>] swsusp_read+0x144/0x230
[    7.916025] [<ffff0000080fa338>] load_image_and_restore+0x58/0x90
[    7.922105] [<ffff0000080fa660>] software_resume+0x2f0/0x338
[    7.927752] [<ffff000008083350>] do_one_initcall+0x38/0x11c
[    7.933314] [<ffff000008b40cc0>] kernel_init_freeable+0x14c/0x1ec
[    7.939395] [<ffff0000087ce564>] kernel_init+0x10/0xfc
[    7.944520] [<ffff000008082e90>] ret_from_fork+0x10/0x40
[    7.949820] Code: d2800022 8b400c21 f9800031 9ac32043 (c85f7c22)
[    7.955909] ---[ end trace 0024a5986e6ff323 ]---
[    7.960529] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Here struct mem_zone_bm_rtree's start_pfn has been returned instead of
struct rtree_node's addr as the node/zone pointers are corrupt after
we walked off the end of the lists during mark_unsafe_pages().

This behaviour was exposed by commit 6dbecfd345 ("PM / hibernate:
Simplify mark_unsafe_pages()"), which caused mark_unsafe_pages() to call
duplicate_memory_bitmap(), which uses memory_bm_find_bit() after walking
off the end of the memory bitmap.

Fixes: 3a20cb1779 (PM / Hibernate: Implement position keeping in radix tree)
Signed-off-by: James Morse <james.morse@arm.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-08-16 13:16:36 +02:00
..
autosleep.c PM / Sleep: avoid 'autosleep' in shutdown progress 2013-07-15 01:31:37 +02:00
console.c PM / sleep: Make pm_prepare_console() return void 2016-06-15 01:26:04 +02:00
hibernate.c PM / hibernate: Restore processor state before using per-CPU variables 2016-08-12 22:50:42 +02:00
Kconfig PM: APM_EMULATION does not depend on PM 2016-01-27 23:20:14 +01:00
main.c PM / sleep: make PM notifiers called symmetrically 2016-06-28 00:38:55 +02:00
Makefile PM / Hibernate: Don't let kasan instrument snapshot.c 2016-06-14 00:38:56 +02:00
power.h x86 / hibernate: Use hlt_play_dead() when resuming from hibernation 2016-07-15 22:42:48 +02:00
poweroff.c power/sysrq: fix inconstistent help message of sysrq key 2013-04-30 17:04:10 -07:00
process.c Merge back earlier suspend/hibernation changes for v4.8. 2016-07-08 23:14:17 +02:00
qos.c PM / QoS: Add debugfs support to view the list of constraints 2015-01-23 22:16:21 +01:00
snapshot.c PM / hibernate: Fix rtree_next_node() to avoid walking off list ends 2016-08-16 13:16:36 +02:00
suspend_test.c PM / sleep: Enhance test_suspend option with repeat capability 2014-09-09 01:48:02 +02:00
suspend.c PM / sleep: make PM notifiers called symmetrically 2016-06-28 00:38:55 +02:00
swap.c PM / hibernate: Introduce test_resume mode for hibernation 2016-07-22 13:57:23 +02:00
user.c PM / sleep: make PM notifiers called symmetrically 2016-06-28 00:38:55 +02:00
wakelock.c PM / autosleep: Use workqueue for user space wakeup sources garbage collector 2015-07-14 21:04:48 +02:00