From 21ea9f5ace3a7317cc3ba1fbc749758021a83136 Mon Sep 17 00:00:00 2001 From: Russ Anderson Date: Wed, 28 Aug 2013 16:35:18 -0700 Subject: drivers/base/memory.c: fix show_mem_removable() to handle missing sections "cat /sys/devices/system/memory/memory*/removable" crashed the system. The problem is that show_mem_removable() is passing a bad pfn to is_mem_section_removable(), which causes if (!node_online(page_to_nid(page))) to blow up. Why is it passing in a bad pfn? The reason is that show_mem_removable() will loop sections_per_block times. sections_per_block is 16, but mem->section_count is 8, indicating holes in this memory block. Checking that the memory section is present before checking to see if the memory section is removable fixes the problem. harp5-sys:~ # cat /sys/devices/system/memory/memory*/removable 0 1 1 1 1 1 1 1 1 1 1 1 1 1 BUG: unable to handle kernel paging request at ffffea00c3200000 IP: [] is_pageblock_removable_nolock+0x1/0x90 PGD 83ffd4067 PUD 37bdfce067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: autofs4 binfmt_misc rdma_ucm rdma_cm iw_cm ib_addr ib_srp scsi_transport_srp scsi_tgt ib_ipoib ib_cm ib_uverbs ib_umad iw_cxgb3 cxgb3 mdio mlx4_en mlx4_ib ib_sa mlx4_core ib_mthca ib_mad ib_core fuse nls_iso8859_1 nls_cp437 vfat fat joydev loop hid_generic usbhid hid hwperf(O) numatools(O) dm_mod iTCO_wdt ipv6 iTCO_vendor_support igb i2c_i801 ioatdma i2c_algo_bit ehci_pci pcspkr lpc_ich i2c_core ehci_hcd ptp sg mfd_core dca rtc_cmos pps_core mperf button xhci_hcd sd_mod crc_t10dif usbcore usb_common scsi_dh_emc scsi_dh_hp_sw scsi_dh_alua scsi_dh_rdac scsi_dh gru(O) xvma(O) xfs crc32c libcrc32c thermal sata_nv processor piix mptsas mptscsih scsi_transport_sas mptbase megaraid_sas fan thermal_sys hwmon ext3 jbd ata_piix ahci libahci libata scsi_mod CPU: 4 PID: 5991 Comm: cat Tainted: G O 3.11.0-rc5-rja-uv+ #10 Hardware name: SGI UV2000/ROMLEY, BIOS SGI UV 2000/3000 series BIOS 01/15/2013 task: ffff88081f034580 ti: ffff880820022000 task.ti: ffff880820022000 RIP: 0010:[] [] is_pageblock_removable_nolock+0x1/0x90 RSP: 0018:ffff880820023df8 EFLAGS: 00010287 RAX: 0000000000040000 RBX: ffffea00c3200000 RCX: 0000000000000004 RDX: ffffea00c30b0000 RSI: 00000000001c0000 RDI: ffffea00c3200000 RBP: ffff880820023e38 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea00c33c0000 R13: 0000160000000000 R14: 6db6db6db6db6db7 R15: 0000000000000001 FS: 00007ffff7fb2700(0000) GS:ffff88083fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffea00c3200000 CR3: 000000081b954000 CR4: 00000000000407e0 Call Trace: show_mem_removable+0x41/0x70 dev_attr_show+0x2a/0x60 sysfs_read_file+0xf7/0x1c0 vfs_read+0xc8/0x130 SyS_read+0x5d/0xa0 system_call_fastpath+0x16/0x1b Signed-off-by: Russ Anderson Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Yinghai Lu Reviewed-by: Yasuaki Ishimatsu Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/base/memory.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 2b7813ec6d02..ec386ee9cb22 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -141,6 +141,8 @@ static ssize_t show_mem_removable(struct device *dev, container_of(dev, struct memory_block, dev); for (i = 0; i < sections_per_block; i++) { + if (!present_section_nr(mem->start_section_nr + i)) + continue; pfn = section_nr_to_pfn(mem->start_section_nr + i); ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION); } -- cgit v1.2.3