• Qian Cai's avatar
    mm/page_ext.c: fix an imbalance with kmemleak · 9f570268
    Qian Cai authored
    [ Upstream commit 0c81585499601acd1d0e1cbf424cabfaee60628c ]
    
    After offlining a memory block, kmemleak scan will trigger a crash, as
    it encounters a page ext address that has already been freed during
    memory offlining.  At the beginning in alloc_page_ext(), it calls
    kmemleak_alloc(), but it does not call kmemleak_free() in
    free_page_ext().
    
        BUG: unable to handle kernel paging request at ffff888453d00000
        PGD 128a01067 P4D 128a01067 PUD 128a04067 PMD 47e09e067 PTE 800ffffbac2ff060
        Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
        CPU: 1 PID: 1594 Comm: bash Not tainted 5.0.0-rc8+ #15
        Hardware name: HP ProLiant DL180 Gen9/ProLiant DL180 Gen9, BIOS U20 10/25/2017
        RIP: 0010:scan_block+0xb5/0x290
        Code: 85 6e 01 00 00 48 b8 00 00 30 f5 81 88 ff ff 48 39 c3 0f 84 5b 01 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 0f 85 87 01 00 00 <4c> 8b 3b e8 f3 0c fa ff 4c 39 3d 0c 6b 4c 01 0f 87 08 01 00 00 4c
        RSP: 0018:ffff8881ec57f8e0 EFLAGS: 00010082
        RAX: 0000000000000000 RBX: ffff888453d00000 RCX: ffffffffa61e5a54
        RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888453d00000
        RBP: ffff8881ec57f920 R08: fffffbfff4ed588d R09: fffffbfff4ed588c
        R10: fffffbfff4ed588c R11: ffffffffa76ac463 R12: dffffc0000000000
        R13: ffff888453d00ff9 R14: ffff8881f80cef48 R15: ffff8881f80cef48
        FS:  00007f6c0e3f8740(0000) GS:ffff8881f7680000(0000) knlGS:0000000000000000
        CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
        CR2: ffff888453d00000 CR3: 00000001c4244003 CR4: 00000000001606a0
        Call Trace:
         scan_gray_list+0x269/0x430
         kmemleak_scan+0x5a8/0x10f0
         kmemleak_write+0x541/0x6ca
         full_proxy_write+0xf8/0x190
         __vfs_write+0xeb/0x980
         vfs_write+0x15a/0x4f0
         ksys_write+0xd2/0x1b0
         __x64_sys_write+0x73/0xb0
         do_syscall_64+0xeb/0xaaa
         entry_SYSCALL_64_after_hwframe+0x44/0xa9
        RIP: 0033:0x7f6c0dad73b8
        Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 65 63 2d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55
        RSP: 002b:00007ffd5b863cb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
        RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f6c0dad73b8
        RDX: 0000000000000005 RSI: 000055a9216e1710 RDI: 0000000000000001
        RBP: 000055a9216e1710 R08: 000000000000000a R09: 00007ffd5b863840
        R10: 000000000000000a R11: 0000000000000246 R12: 00007f6c0dda9780
        R13: 0000000000000005 R14: 00007f6c0dda4740 R15: 0000000000000005
        Modules linked in: nls_iso8859_1 nls_cp437 vfat fat kvm_intel kvm irqbypass efivars ip_tables x_tables xfs sd_mod ahci libahci igb i2c_algo_bit libata i2c_core dm_mirror dm_region_hash dm_log dm_mod efivarfs
        CR2: ffff888453d00000
        ---[ end trace ccf646c7456717c5 ]---
        Kernel panic - not syncing: Fatal exception
        Shutting down cpus with NMI
        Kernel Offset: 0x24c00000 from 0xffffffff81000000 (relocation range:
        0xffffffff80000000-0xffffffffbfffffff)
        ---[ end Kernel panic - not syncing: Fatal exception ]---
    
    Link: http://lkml.kernel.org/r/20190227173147.75650-1-cai@lca.pwSigned-off-by: 's avatarQian Cai <cai@lca.pw>
    Reviewed-by: 's avatarCatalin Marinas <catalin.marinas@arm.com>
    Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: 's avatarSasha Levin <sashal@kernel.org>
    9f570268