Revision dbe409e4f5e5075bd9ff7f8dd5c627abf3ee38c1 authored by Mike Kravetz on 11 December 2015, 21:40:52 UTC, committed by Linus Torvalds on 12 December 2015, 18:15:34 UTC
Dmitry Vyukov reported the following memory leak unreferenced object 0xffff88002eaafd88 (size 32): comm "a.out", pid 5063, jiffies 4295774645 (age 15.810s) hex dump (first 32 bytes): 28 e9 4e 63 00 88 ff ff 28 e9 4e 63 00 88 ff ff (.Nc....(.Nc.... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: kmalloc include/linux/slab.h:458 region_chg+0x2d4/0x6b0 mm/hugetlb.c:398 __vma_reservation_common+0x2c3/0x390 mm/hugetlb.c:1791 vma_needs_reservation mm/hugetlb.c:1813 alloc_huge_page+0x19e/0xc70 mm/hugetlb.c:1845 hugetlb_no_page mm/hugetlb.c:3543 hugetlb_fault+0x7a1/0x1250 mm/hugetlb.c:3717 follow_hugetlb_page+0x339/0xc70 mm/hugetlb.c:3880 __get_user_pages+0x542/0xf30 mm/gup.c:497 populate_vma_page_range+0xde/0x110 mm/gup.c:919 __mm_populate+0x1c7/0x310 mm/gup.c:969 do_mlock+0x291/0x360 mm/mlock.c:637 SYSC_mlock2 mm/mlock.c:658 SyS_mlock2+0x4b/0x70 mm/mlock.c:648 Dmitry identified a potential memory leak in the routine region_chg, where a region descriptor is not free'ed on an error path. However, the root cause for the above memory leak resides in region_del. In this specific case, a "placeholder" entry is created in region_chg. The associated page allocation fails, and the placeholder entry is left in the reserve map. This is "by design" as the entry should be deleted when the map is released. The bug is in the region_del routine which is used to delete entries within a specific range (and when the map is released). region_del did not handle the case where a placeholder entry exactly matched the start of the range range to be deleted. In this case, the entry would not be deleted and leaked. The fix is to take these special placeholder entries into account in region_del. The region_chg error path leak is also fixed. Fixes: feba16e25a57 ("mm/hugetlb: add region_del() to delete a specific range of entries") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: <stable@vger.kernel.org> [4.3+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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m5208evb_defconfig
CONFIG_LOG_BUF_SHIFT=14
CONFIG_EXPERT=y
# CONFIG_KALLSYMS is not set
# CONFIG_FUTEX is not set
# CONFIG_EPOLL is not set
# CONFIG_SIGNALFD is not set
# CONFIG_TIMERFD is not set
# CONFIG_EVENTFD is not set
# CONFIG_AIO is not set
# CONFIG_VM_EVENT_COUNTERS is not set
# CONFIG_COMPAT_BRK is not set
# CONFIG_BLK_DEV_BSG is not set
# CONFIG_IOSCHED_DEADLINE is not set
# CONFIG_IOSCHED_CFQ is not set
# CONFIG_MMU is not set
# CONFIG_4KSTACKS is not set
CONFIG_RAMBASE=0x40000000
CONFIG_RAMSIZE=0x2000000
CONFIG_VECTORBASE=0x40000000
CONFIG_KERNELBASE=0x40020000
CONFIG_BINFMT_FLAT=y
CONFIG_NET=y
CONFIG_PACKET=y
CONFIG_UNIX=y
CONFIG_INET=y
# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
# CONFIG_INET_XFRM_MODE_TUNNEL is not set
# CONFIG_INET_XFRM_MODE_BEET is not set
# CONFIG_INET_LRO is not set
# CONFIG_INET_DIAG is not set
# CONFIG_IPV6 is not set
# CONFIG_FW_LOADER is not set
CONFIG_MTD=y
CONFIG_MTD_BLOCK=y
CONFIG_MTD_RAM=y
CONFIG_MTD_UCLINUX=y
CONFIG_BLK_DEV_RAM=y
CONFIG_NETDEVICES=y
CONFIG_FEC=y
# CONFIG_INPUT is not set
# CONFIG_SERIO is not set
# CONFIG_VT is not set
# CONFIG_UNIX98_PTYS is not set
CONFIG_SERIAL_MCF=y
CONFIG_SERIAL_MCF_BAUDRATE=115200
CONFIG_SERIAL_MCF_CONSOLE=y
# CONFIG_HW_RANDOM is not set
# CONFIG_HWMON is not set
# CONFIG_USB_SUPPORT is not set
CONFIG_EXT2_FS=y
# CONFIG_FILE_LOCKING is not set
# CONFIG_DNOTIFY is not set
# CONFIG_SYSFS is not set
CONFIG_ROMFS_FS=y
CONFIG_ROMFS_BACKED_BY_MTD=y
# CONFIG_NETWORK_FILESYSTEMS is not set
CONFIG_BOOTPARAM=y
CONFIG_BOOTPARAM_STRING="root=/dev/mtdblock0"
CONFIG_FULLDEBUG=y
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