From 8a356ce38e134b3b09b439e88dc770f8f5567648 Mon Sep 17 00:00:00 2001 From: Wen Congyang Date: Fri, 22 Feb 2013 16:33:21 -0800 Subject: [PATCH] memory-hotplug: consider compound pages when free memmap usemap could also be allocated as compound pages. Should also consider compound pages when freeing memmap. If we don't fix it, there could be problems when we free vmemmap pagetables which are stored in compound pages. The old pagetables will not be freed properly, and when we add the memory again, no new pagetable will be created. And the old pagetable entry is used, than the kernel will panic. The call trace is like the following: BUG: unable to handle kernel paging request at ffffea0040000000 IP: [] sparse_add_one_section+0xef/0x166 PGD 7ff7d4067 PUD 78e035067 PMD 78e11d067 PTE 0 Oops: 0002 [#1] SMP Modules linked in: ip6table_filter ip6_tables ebtable_nat ebtables nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle iptable_filter ip_tables bridge stp llc sunrpc binfmt_misc dm_mirror dm_region_hash dm_log dm_mod vhost_net macvtap macvlan tun uinput iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm crc32c_intel microcode pcspkr sg lpc_ich mfd_core i2c_i801 i2c_core i7core_edac edac_core ioatdma e1000e igb dca ptp pps_core sd_mod crc_t10dif megaraid_sas mptsas mptscsih mptbase scsi_transport_sas scsi_mod CPU 0 Pid: 4, comm: kworker/0:0 Tainted: G W 3.8.0-rc3-phy-hot-remove+ #3 FUJITSU-SV PRIMEQUEST 1800E/SB RIP: 0010:[] [] sparse_add_one_section+0xef/0x166 RSP: 0018:ffff8807bdcb35d8 EFLAGS: 00010006 RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000200000 RDX: ffff88078df01148 RSI: 0000000000000282 RDI: ffffea0040000000 RBP: ffff8807bdcb3618 R08: 4cf05005b019467a R09: 0cd98fa09631467a R10: 0000000000000000 R11: 0000000000030e20 R12: 0000000000008000 R13: ffffea0040000000 R14: ffff88078df66248 R15: ffff88078ea13b10 FS: 0000000000000000(0000) GS:ffff8807c1a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: ffffea0040000000 CR3: 0000000001c0c000 CR4: 00000000000007f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process kworker/0:0 (pid: 4, threadinfo ffff8807bdcb2000, task ffff8807bde18000) Call Trace: __add_pages+0x85/0x120 arch_add_memory+0x71/0xf0 add_memory+0xd6/0x1f0 acpi_memory_device_add+0x170/0x20c acpi_device_probe+0x50/0x18a really_probe+0x6c/0x320 driver_probe_device+0x47/0xa0 __device_attach+0x53/0x60 bus_for_each_drv+0x6c/0xa0 device_attach+0xa8/0xc0 bus_probe_device+0xb0/0xe0 device_add+0x301/0x570 device_register+0x1e/0x30 acpi_device_register+0x1d8/0x27c acpi_add_single_object+0x1df/0x2b9 acpi_bus_check_add+0x112/0x18f acpi_ns_walk_namespace+0x105/0x255 acpi_walk_namespace+0xcf/0x118 acpi_bus_scan+0x5b/0x7c acpi_bus_add+0x2a/0x2c container_notify_cb+0x112/0x1a9 acpi_ev_notify_dispatch+0x46/0x61 acpi_os_execute_deferred+0x27/0x34 process_one_work+0x20e/0x5c0 worker_thread+0x12e/0x370 kthread+0xee/0x100 ret_from_fork+0x7c/0xb0 Code: 00 00 48 89 df 48 89 45 c8 e8 3e 71 b1 ff 48 89 c2 48 8b 75 c8 b8 ef ff ff ff f6 02 01 75 4b 49 63 cc 31 c0 4c 89 ef 48 c1 e1 06 aa 48 8b 02 48 83 c8 01 48 85 d2 48 89 02 74 29 a8 01 74 25 RIP [] sparse_add_one_section+0xef/0x166 RSP CR2: ffffea0040000000 ---[ end trace e7f94e3a34c442d4 ]--- Kernel panic - not syncing: Fatal exception Signed-off-by: Wen Congyang Signed-off-by: Tang Chen Cc: Jiang Liu Cc: Jianguo Wu Cc: Kamezawa Hiroyuki Cc: Lai Jiangshan Cc: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/sparse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/sparse.c b/mm/sparse.c index 46f6ea47d9ab..cff97960f1d7 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -698,7 +698,7 @@ static void free_section_usemap(struct page *memmap, unsigned long *usemap) /* * Check to see if allocation came from hot-plug-add */ - if (PageSlab(usemap_page)) { + if (PageSlab(usemap_page) || PageCompound(usemap_page)) { kfree(usemap); if (memmap) __kfree_section_memmap(memmap, PAGES_PER_SECTION); -- 2.30.2