[Bug 216073] [s390x] kernel BUG at mm/usercopy.c:101! usercopy: Kernel memory exposure attempt detected from vmalloc 'n o area' (offset 0, size 1)!

bugzilla-daemon
2022-06-12T04:42:48Z

--- Comment #10 from Zorro Lang (zlang@redhat.com) ---
On Wed, Jun 08, 2022 at 09:13:12PM +0200, Alexander Gordeev wrote:
> On Wed, Jun 08, 2022 at 10:19:22AM +0800, Zorro Lang wrote:
> > One of the test environment details as [1]. The xfstests config as [2].
> > It's easier to reproduce on 64k directory size xfs by running xfstests
> > auto group.
>
>
> Thanks for the details, Zorro!
>
> Do you create test and scratch device with xfs_io, as README suggests?
> If yes, what are sizes of the files?
> Also, do you run always xfs/auto or xfs/294 hits for you reliably?

Looks likt it's not a s390x specific bug, I just hit this issue once (not 100%
reproducible) on aarch64 with linux v5.19.0-rc1+ [1]. So back to cc linux-mm
to get more review.

Thanks,
Zorro

[1]
[ 980.200947] usercopy: Kernel memory exposure attempt detected from vmalloc
'no area' (offset 0, size 1)!
[ 980.200968] ------------[ cut here ]------------
[ 980.200969] kernel BUG at mm/usercopy.c:101!
[ 980.201081] Internal error: Oops - BUG: 0 [#1] SMP
[ 980.224192] Modules linked in: rfkill arm_spe_pmu mlx5_ib ast
drm_vram_helper drm_ttm_helper ttm ib_uverbs acpi_ipmi drm_kms_helper ipmi_ssif
fb_sys_fops syscopyarea sysfillrect ib_core sysimgblt arm_cmn arm_dmc620_pmu
arm_dsu_pmu cppc_cpufreq sunrpc vfat fat drm fuse xfs libcrc32c mlx5_core
crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce sbsa_gwdt nvme igb mlxfw
nvme_core tls i2c_algo_bit psample pci_hyperv_intf i2c_designware_platform
i2c_designware_core xgene_hwmon ipmi_devintf ipmi_msghandler
[ 980.268449] CPU: 42 PID: 121940 Comm: rm Kdump: loaded Not tainted
5.19.0-rc1+ #1
[ 980.275921] Hardware name: GIGABYTE R272-P30-JG/MP32-AR0-JG, BIOS F16f (SCP:
1.06.20210615) 07/01/2021
[ 980.285214] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 980.292165] pc : usercopy_abort+0x78/0x7c
[ 980.296167] lr : usercopy_abort+0x78/0x7c
[ 980.300166] sp : ffff80002b007730
[ 980.303469] x29: ffff80002b007740 x28: ffff80002b007cc0 x27:
ffffdc5683ecc880
[ 980.310595] x26: 1ffff00005600f9b x25: ffffdc5681c90000 x24:
ffff80002b007cdc
[ 980.317722] x23: ffff800041a0004a x22: 0000000000000001 x21:
0000000000000001
[ 980.324848] x20: 0000000000000000 x19: ffff800041a00049 x18:
0000000000000000
[ 980.331974] x17: 2720636f6c6c616d x16: 76206d6f72662064 x15:
6574636574656420
[ 980.339101] x14: 74706d6574746120 x13: 21293120657a6973 x12:
ffff6106cbc4c03f
[ 980.346227] x11: 1fffe106cbc4c03e x10: ffff6106cbc4c03e x9 :
ffffdc5681f36e30
[ 980.353353] x8 : ffff08365e2601f7 x7 : 0000000000000001 x6 :
ffff6106cbc4c03e
[ 980.360480] x5 : ffff08365e2601f0 x4 : 1fffe10044b11801 x3 :
0000000000000000
[ 980.367606] x2 : 0000000000000000 x1 : ffff08022588c000 x0 :
000000000000005c
[ 980.374733] Call trace:
[ 980.377167] usercopy_abort+0x78/0x7c
[ 980.380819] check_heap_object+0x3dc/0x3e0
[ 980.384907] __check_object_size.part.0+0x6c/0x1f0
[ 980.389688] __check_object_size+0x24/0x30
[ 980.393774] filldir64+0x548/0x84c
[ 980.397165] xfs_dir2_block_getdents+0x404/0x960 [xfs]
[ 980.402437] xfs_readdir+0x3c4/0x4b0 [xfs]
[ 980.406652] xfs_file_readdir+0x6c/0xa0 [xfs]
[ 980.411127] iterate_dir+0x3a4/0x500
[ 980.414691] __do_sys_getdents64+0xb0/0x230
[ 980.418863] __arm64_sys_getdents64+0x70/0xa0
[ 980.423209] invoke_syscall.constprop.0+0xd8/0x1d0
[ 980.427991] el0_svc_common.constprop.0+0x224/0x2bc
[ 980.432858] do_el0_svc+0x4c/0x90
[ 980.436163] el0_svc+0x5c/0x140
[ 980.439294] el0t_64_sync_handler+0xb4/0x130
[ 980.443553] el0t_64_sync+0x174/0x178
[ 980.447206] Code: f90003e3 aa0003e3 91098100 97ffe24b (d4210000)
[ 980.453292] SMP: stopping secondary CPUs
[ 980.458162] Starting crashdump kernel...
[ 980.462073] Bye!

>
> Thanks!