On 21/10/2021 13:20, Arnd Bergmann wrote:
On Thu, Oct 21, 2021 at 2:01 PM Naresh Kamboju
<naresh.kamboju@xxxxxxxxxx> wrote:
Following KASAN BUG noticed on linux next 20211021 while booting qemu-arm64
with allmodconfig.
[ 77.730367][ T5] Freed by task 1:
[ 77.732009][ T5] kasan_save_stack+0x30/0x80
[ 77.734083][ T5] kasan_set_track+0x30/0x80
[ 77.736085][ T5] kasan_set_free_info+0x34/0x80
[ 77.738261][ T5] ____kasan_slab_free+0xfc/0x1c0
[ 77.740433][ T5] __kasan_slab_free+0x3c/0x80
[ 77.742518][ T5] slab_free_freelist_hook+0x1d4/0x2c0
[ 77.744892][ T5] kfree+0x160/0x300
[ 77.746618][ T5] blktrans_dev_release+0x64/0x100
[ 77.748821][ T5] del_mtd_blktrans_dev+0x1c0/0x240
[ 77.751079][ T5] mtdblock_remove_dev+0x28/0x80
[ 77.753246][ T5] blktrans_notify_remove+0xa4/0x140
[ 77.755507][ T5] del_mtd_device+0x84/0x1c0
[ 77.757541][ T5] mtd_device_unregister+0x90/0xc0
[ 77.759764][ T5] physmap_flash_remove+0x58/0x180
[ 77.762012][ T5] platform_remove+0x48/0xc0
[ 77.764032][ T5] __device_release_driver+0x1dc/0x340
[ 77.766393][ T5] driver_detach+0x138/0x200
[ 77.768396][ T5] bus_remove_driver+0x100/0x180
[ 77.770554][ T5] driver_unregister+0x64/0xc0
[ 77.772633][ T5] platform_driver_unregister+0x28/0x80
[ 77.775042][ T5] physmap_init+0xc4/0xfc
[ 77.776994][ T5] do_one_initcall+0xb0/0x2c0
[ 77.779028][ T5] do_initcalls+0x17c/0x244
[ 77.781023][ T5] kernel_init_freeable+0x2d4/0x378
[ 77.783269][ T5] kernel_init+0x34/0x180
[ 77.785196][ T5] ret_from_fork+0x10/0x20
[ 77.787135][ T5]
...
full boot log link,
https://pastebin.com/xL5MYSD6
I think this is related to an earlier bug that Anders reported a while ago,
see [1]. I had looked at it originally, and found that this probably a
device that gets probed from CONFIG_MTD_PHYSMAP_COMPAT
and then freed again immediately after we find the device does not
exist, starting with commit dcb3e137ce9b ("[MTD] physmap: make
physmap compat explicit").
It's not really the fault of CONFIG_MTD_PHYSMAP_COMPAT
describing a nonexisting device, but instead it's something in the
cleanup path.
Maybe there is more than one issue, but the fix I mentioned in my
earlier reply resolves a UAF which can I trigger on my system:
[ 674.333618] FAT-fs (sda1): unable to read boot sector to mark fs as dirty
[ 674.422877]
==================================================================
[ 674.430097] BUG: KASAN: use-after-free in
blk_mq_sched_tags_teardown+0xb4/0x12c
[ 674.437412] Read of size 4 at addr ffff001053f40100 by task umount/557
[ 674.443934]
[ 674.445418] CPU: 6 PID: 557 Comm: umount Not tainted
5.15.0-rc3-00045-g000f88ac8830 #420
[ 674.453502] Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon
D05 IT21 Nemo 2.0 RC0 04/18/2018
[ 674.462626] Call trace:
[ 674.465063] dump_backtrace+0x0/0x2b4
[ 674.468724] show_stack+0x1c/0x30
[ 674.472036] dump_stack_lvl+0x68/0x84
[ 674.475695] print_address_description.constprop.0+0x74/0x2b8
[ 674.481438] kasan_report+0x1e4/0x24c
[ 674.485096] __asan_load4+0x98/0xd0
[ 674.488579] blk_mq_sched_tags_teardown+0xb4/0x12c
[ 674.493366] blk_mq_exit_sched+0x110/0x140
[ 674.497459] __elevator_exit+0x38/0x60
[ 674.501203] blk_release_queue+0x10c/0x1cc
[ 674.505295] kobject_put+0xac/0x180
[ 674.508780] blk_put_queue+0x18/0x24
[ 674.512350] disk_release+0x64/0x90
[ 674.515836] device_release+0x98/0x110
[ 674.519581] kobject_put+0xac/0x180
[ 674.523065] put_device+0x18/0x30
[ 674.526374] put_disk+0x30/0x44
[ 674.529511] part_release+0x28/0x4c
[ 674.532993] device_release+0x98/0x110
[ 674.536737] kobject_put+0xac/0x180
[ 674.540221] put_device+0x18/0x30
[ 674.543531] blkdev_put+0xe4/0x340
[ 674.546930] kill_block_super+0x60/0xa0
[ 674.550762] deactivate_locked_super+0x78/0x104
[ 674.555289] deactivate_super+0x90/0xac
[ 674.559121] cleanup_mnt+0x164/0x214
[ 674.562691] __cleanup_mnt+0x18/0x24
[ 674.566260] task_work_run+0xb8/0x1cc
[ 674.569918] do_notify_resume+0x11a8/0x1abc
[ 674.574098] el0_svc+0x6c/0x7c
[ 674.577148] el0t_64_sync_handler+0x1a8/0x1b0
[ 674.581500] el0t_64_sync+0x1a0/0x1a4
[ 674.585157]
[ 674.586639] The buggy address belongs to the page:
[ 674.591420] page:(____ptrval____) refcount:0 mapcount:-128
mapping:0000000000000000 index:0x0 pfn:0x1053f40
[ 674.601154] flags: 0xbfffc0000000000(node=0|zone=2|lastcpupid=0xffff)
[ 674.607594] raw: 0bfffc0000000000 fffffc00415ff008 ffff0017fbffebb0
0000000000000000
[ 674.615331] raw: 0000000000000000 0000000000000006 00000000ffffff7f
0000000000000000
[ 674.623065] page dumped because: kasan: bad access detected
[ 674.628628]
[ 674.630109] Memory state around the buggy address:
[ 674.634891] ffff001053f40000: ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff
[ 674.642105] ffff001053f40080: ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff
[ 674.649319] >ffff001053f40100: ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff
[ 674.656531] ^
[ 674.659751] ffff001053f40180: ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff
[ 674.666964] ffff001053f40200: ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff
[ 674.674177]
==================================================================
[ 674.681389] Disabling lock debugging due to kernel taint
root@(none)$
root@(none)$
Note that my baseline includes recent block changes which would be on
next 20211021
Thanks,
John
Arnd
[1] https://lore.kernel.org/linux-mtd/CADYN=9Kjw_3cDGAvh9=+nNwdYof1kUPKG-SUOP5FsQhZ+gz62Q@xxxxxxxxxxxxxx/
.
