Messages in this thread | | | From | (Eric W. Biederman) | Date | Tue, 19 Oct 2021 10:49:53 -0500 | Subject | Re: [mm] 6128b3af2a: UBSAN:shift-out-of-bounds_in(null) |
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kernel test robot <oliver.sang@intel.com> writes:
> Greeting, > > FYI, we noticed the following commit (built with clang-14): > > commit: 6128b3af2a5e42386aa7faf37609b57f39fb7d00 ("mm: ignore MAP_DENYWRITE in ksys_mmap_pgoff()") > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
I believe this failure is misattributed. Perhaps your reproducer only intermittently reproduces the problem?
The change in question only contains
flags &= ~MAP_DENYWRITE
After all of the other users of MAP_DENYWRITE had been removed from the kernel. So I don't see how it could possibly be responsible for the reported shift out of bounds problem.
Eric
> in testcase: trinity > version: trinity-i386-4d2343bd-1_20200320 > with following parameters: > > runtime: 300s > > test-description: Trinity is a linux system call fuzz tester. > test-url: http://codemonkey.org.uk/projects/trinity/ > > > on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G > > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): > > > +---------------------------------------------+------------+------------+ > | | 8d0920bde5 | 6128b3af2a | > +---------------------------------------------+------------+------------+ > | UBSAN:shift-out-of-bounds_in(null) | 0 | 9 | > +---------------------------------------------+------------+------------+ > > > If you fix the issue, kindly add following tag > Reported-by: kernel test robot <oliver.sang@intel.com> > > > > [ 126.758570][ T3293] ================================================================================ > [ 126.758949][ T3293] UBSAN: shift-out-of-bounds in (null):0:0 > [ 126.759174][ T3293] BUG: kernel NULL pointer dereference, address: 00000000 > [ 126.759447][ T3293] #PF: supervisor read access in kernel mode > [ 126.759676][ T3293] #PF: error_code(0x0000) - not-present page > [ 126.759905][ T3293] *pde = 00000000 > [ 126.760047][ T3293] Oops: 0000 [#1] SMP > [ 126.760205][ T3293] CPU: 1 PID: 3293 Comm: trinity-c4 Not tainted 5.14.0-00006-g6128b3af2a5e #1 > [ 126.760541][ T3293] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 > [ 126.760890][ T3293] EIP: __ubsan_handle_shift_out_of_bounds+0x88/0x350 > [ 126.761147][ T3293] Code: 00 83 c4 04 7f 23 47 04 7f 23 47 04 ff 37 68 ef ff 37 68 ef e3 77 d0 d7 e3 77 d0 d7 00 8b 45 f0 00 8b 45 f0 c4 14 66 83 c4 14 <66> 83 66 > 83 3f 00 66 83 3f 00 00 00 66 83 00 00 66 83 b9 01 00 00 > [ 126.761889][ T3293] EAX: 00000000 EBX: f345b500 ECX: 00000027 EDX: eba9ce40 > [ 126.762159][ T3293] ESI: 00000046 EDI: 00000000 EBP: f3575f40 ESP: f3575ecc > [ 126.762428][ T3293] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010286 > [ 126.762718][ T3293] CR0: 80050033 CR2: 00000000 CR3: 33464000 CR4: 000406d0 > [ 126.762989][ T3293] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > [ 126.763259][ T3293] DR6: fffe0ff0 DR7: 00000400 > [ 126.763436][ T3293] Call Trace: > [ 126.763562][ T3293] ? rcu_lock_acquire+0x30/0x30 > [ 126.763749][ T3293] ? rcu_read_lock_sched_held+0x31/0x70 > [ 126.763960][ T3293] ksys_mmap_pgoff+0x1fc/0x290 > [ 126.764146][ T3293] __ia32_sys_mmap_pgoff+0x1c/0x30 > [ 126.764343][ T3293] do_int80_syscall_32+0x39/0x80 > [ 126.764532][ T3293] entry_INT80_32+0x10d/0x10d > [ 126.764709][ T3293] EIP: 0xb7fbda02 > [ 126.764848][ T3293] Code: 95 01 00 05 25 36 02 00 83 ec 14 8d 80 e8 99 ff ff 50 6a 02 e8 1f ff 00 00 c7 04 24 7f 00 00 00 e8 7e 87 01 00 66 90 90 cd 80 <c3> 8d b6 > 00 00 00 00 8d bc 27 00 00 00 00 8b 1c 24 c3 8d b6 00 00 > [ 126.765591][ T3293] EAX: ffffffda EBX: 00000000 ECX: 00001000 EDX: 55dd7eb6 > [ 126.765859][ T3293] ESI: f0bd6374 EDI: ffffffff EBP: 00000000 ESP: bf9964d8 > [ 126.766129][ T3293] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000296 > [ 126.766419][ T3293] Modules linked in: aesni_intel crypto_simd qemu_fw_cfg autofs4 > [ 126.766715][ T3293] CR2: 0000000000000000 > [ 126.766894][ T3293] ---[ end trace e6000e119f0dc7f3 ]--- > [ 126.767105][ T3293] EIP: __ubsan_handle_shift_out_of_bounds+0x88/0x350 > [ 126.767361][ T3293] Code: 00 83 c4 04 7f 23 47 04 7f 23 47 04 ff 37 68 ef ff 37 68 ef e3 77 d0 d7 e3 77 d0 d7 00 8b 45 f0 00 8b 45 f0 c4 14 66 83 c4 14 <66> 83 66 83 3f 00 66 83 3f 00 00 00 66 83 00 00 66 83 b9 01 00 00 > [ 126.768112][ T3293] EAX: 00000000 EBX: f345b500 ECX: 00000027 EDX: eba9ce40 > [ 126.768384][ T3293] ESI: 00000046 EDI: 00000000 EBP: f3575f40 ESP: f3575ecc > [ 126.768657][ T3293] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010286 > [ 126.768947][ T3293] CR0: 80050033 CR2: 00000000 CR3: 33464000 CR4: 000406d0 > [ 126.769223][ T3293] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > [ 126.769496][ T3293] DR6: fffe0ff0 DR7: 00000400 > [ 126.769680][ T3293] Kernel panic - not syncing: Fatal exception > [ 126.769946][ T3293] Kernel Offset: disabled > > > > To reproduce: > > # build kernel > cd linux > cp config-5.14.0-00006-g6128b3af2a5e .config > make HOSTCC=clang-14 CC=clang-14 ARCH=i386 olddefconfig prepare modules_prepare bzImage > > git clone https://github.com/intel/lkp-tests.git > cd lkp-tests > bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email > > # if come across any failure that blocks the test, > # please remove ~/.lkp and /lkp dir to run from a clean state. > > > > --- > 0DAY/LKP+ Test Infrastructure Open Source Technology Center > https://lists.01.org/hyperkitty/list/lkp@lists.01.org Intel Corporation > > Thanks, > Oliver Sang
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