On Sat, Aug 17, 2024 at 09:50:29AM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 8867bbd4a056 mm: arm64: Fix the out-of-bounds issue in con..
It looks like that's somewhat stale; that commit no longer exists in the arm64/linux.git for-kernelci branch. > git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git > for-kernelci > console output: https://syzkaller.appspot.com/x/log.txt?x=14240e91980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=1bc88a9f65787e86 > dashboard link: https://syzkaller.appspot.com/bug?extid=e199425e3ce5a18d178c > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) > 2.40 > userspace arch: arm64 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: > https://storage.googleapis.com/syzbot-assets/5ef30d34e749/disk-8867bbd4.raw.xz > vmlinux: > https://storage.googleapis.com/syzbot-assets/a21c2389ebfb/vmlinux-8867bbd4.xz > kernel image: > https://storage.googleapis.com/syzbot-assets/9720b12c3f99/Image-8867bbd4.gz.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+e199425e3ce5a18d1...@syzkaller.appspotmail.com > > bcachefs (loop4): done starting filesystem > ------------[ cut here ]------------ > virt_to_phys used for non-linear address: fffffffffffffff2 > (0xfffffffffffffff2) That address looks like an error pointer (it's -14 AKA -EFAULT), though it's also possible that this is just an offset of -14 from a NULL pointer. > WARNING: CPU: 0 PID: 6849 at arch/arm64/mm/physaddr.c:15 > __virt_to_phys+0xc4/0x138 arch/arm64/mm/physaddr.c:12 > Modules linked in: > CPU: 0 PID: 6849 Comm: syz.4.112 Tainted: G W > 6.10.0-rc2-syzkaller-g8867bbd4a056 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 06/27/2024 > pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : __virt_to_phys+0xc4/0x138 arch/arm64/mm/physaddr.c:12 > lr : __virt_to_phys+0xc4/0x138 arch/arm64/mm/physaddr.c:12 > sp : ffff8000a03b6c00 > x29: ffff8000a03b6c00 x28: 0000000000000002 x27: 1ffff00014076d98 > x26: 1ffff00014076d94 x25: dfff800000000000 x24: fffffffffffffff2 > x23: ffff0000c96a2220 x22: 000f600000000000 x21: 000000000000002d > x20: fffffffffffffff2 x19: 000ffffffffffff2 x18: 1fffe000367a01de > x17: ffff80008f3bd000 x16: ffff80008033878c x15: 0000000000000001 > x14: 1fffe000367a2e00 x13: 0000000000000000 x12: 0000000000000003 > x11: 0000000000000001 x10: 0000000000000003 x9 : c187ea6d31d9c500 > x8 : c187ea6d31d9c500 x7 : ffff8000802aebf8 x6 : 0000000000000000 > x5 : 0000000000000001 x4 : 0000000000000001 x3 : 0000000000000000 > x2 : ffff0000dc418000 x1 : ffff80008b3800a0 x0 : ffff8001249f9000 > Call trace: > __virt_to_phys+0xc4/0x138 arch/arm64/mm/physaddr.c:12 > virt_to_phys arch/arm64/include/asm/memory.h:368 [inline] > virt_to_pfn arch/arm64/include/asm/memory.h:382 [inline] > virt_to_folio include/linux/mm.h:1313 [inline] > kfree+0xa4/0x3f4 mm/slub.c:4549 > bch2_ioctl_fsck_online+0x358/0x580 fs/bcachefs/chardev.c:853 AFAICT that's the kfree in the following block: char *optstr = strndup_user((char __user *)(unsigned long) arg.opts, 1 << 16); ret = PTR_ERR_OR_ZERO(optstr) ?: bch2_parse_mount_opts(c, &thr->opts, NULL, optstr); if (!IS_ERR(optstr)) kfree(optstr); ... where (in v6.11-rc4) that kfree(optstr) is on line 853, and the prior strndup_user() can return -EFAULT, but that *should* be caught by the '!IS_ERR(optstr)' check. Another possibility is that the kfree is a tail-call at the end of bch2_parse_mount_opts(), and somehow 'copied_opts_start' there is -EFAULT, but I cannot immeditately see how that could be the case either. Mark. > bch2_fs_ioctl+0x23ec/0x3980 fs/bcachefs/chardev.c:927 > bch2_fs_file_ioctl+0x7b8/0x2460 fs/bcachefs/fs-ioctl.c:539 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:907 [inline] > __se_sys_ioctl fs/ioctl.c:893 [inline] > __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893 > __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] > invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 > el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 > do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 > el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 > el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 > el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 > irq event stamp: 80570 > hardirqs last enabled at (80569): [<ffff8000802aec98>] > raw_spin_rq_unlock_irq kernel/sched/sched.h:1418 [inline] > hardirqs last enabled at (80569): [<ffff8000802aec98>] > finish_lock_switch+0xbc/0x1e4 kernel/sched/core.c:5162 > hardirqs last disabled at (80570): [<ffff80008b1fe010>] el1_dbg+0x24/0x80 > arch/arm64/kernel/entry-common.c:470 > softirqs last enabled at (80550): [<ffff8000801ea530>] softirq_handle_end > kernel/softirq.c:400 [inline] > softirqs last enabled at (80550): [<ffff8000801ea530>] > handle_softirqs+0xa60/0xc34 kernel/softirq.c:582 > softirqs last disabled at (80541): [<ffff800080020de8>] > __do_softirq+0x14/0x20 kernel/softirq.c:588 > ---[ end trace 0000000000000000 ]--- > Unable to handle kernel paging request at virtual address ffffffffc375ffc8 > KASAN: maybe wild-memory-access in range > [0x0003fffe1baffe40-0x0003fffe1baffe47] > Mem abort info: > ESR = 0x0000000096000006 > EC = 0x25: DABT (current EL), IL = 32 bits > SET = 0, FnV = 0 > EA = 0, S1PTW = 0 > FSC = 0x06: level 2 translation fault > Data abort info: > ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000 > CM = 0, WnR = 0, TnD = 0, TagAccess = 0 > GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 > swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000001ac6da000 > [ffffffffc375ffc8] pgd=0000000000000000, p4d=00000001afff8003, > pud=00000001afff9003, pmd=0000000000000000 > Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP > Modules linked in: > CPU: 0 PID: 6849 Comm: syz.4.112 Tainted: G W > 6.10.0-rc2-syzkaller-g8867bbd4a056 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 06/27/2024 > pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : _compound_head include/linux/page-flags.h:245 [inline] > pc : virt_to_folio include/linux/mm.h:1315 [inline] > pc : kfree+0xbc/0x3f4 mm/slub.c:4549 > lr : virt_to_phys arch/arm64/include/asm/memory.h:368 [inline] > lr : virt_to_pfn arch/arm64/include/asm/memory.h:382 [inline] > lr : virt_to_folio include/linux/mm.h:1313 [inline] > lr : kfree+0xa4/0x3f4 mm/slub.c:4549 > sp : ffff8000a03b6c30 > x29: ffff8000a03b6c40 x28: 0000000000000002 x27: 1ffff00014076d98 > x26: 1ffff00014076d94 x25: dfff800000000000 x24: fffffffffffffff2 > x23: ffff0000c96a2220 x22: ffff0000ef24a2d0 x21: fffffffffffffff2 > x20: ffffffffc375ffc0 x19: ffff8000828128a8 x18: 1fffe000367a01de > x17: ffff80008f3bd000 x16: ffff80008033878c x15: 0000000000000001 > x14: 1fffe000367a2e00 x13: 0000000000000000 x12: 0000000000000003 > x11: 0000000000040000 x10: 0000000000015b3d x9 : 00003e000375ffc0 > x8 : ffffc1ffc0000000 x7 : ffff8000802aebf8 x6 : 0000000000000000 > x5 : 0000000000000001 x4 : 0000000000000001 x3 : 0000000000000000 > x2 : ffff0000dc418000 x1 : ffff80008b3800a0 x0 : 000080011d7ffff2 > Call trace: > virt_to_folio include/linux/mm.h:1313 [inline] > kfree+0xbc/0x3f4 mm/slub.c:4549 > bch2_ioctl_fsck_online+0x358/0x580 fs/bcachefs/chardev.c:853 > bch2_fs_ioctl+0x23ec/0x3980 fs/bcachefs/chardev.c:927 > bch2_fs_file_ioctl+0x7b8/0x2460 fs/bcachefs/fs-ioctl.c:539 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:907 [inline] > __se_sys_ioctl fs/ioctl.c:893 [inline] > __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:893 > __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] > invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 > el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 > do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 > el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 > el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 > el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 > Code: 927acd29 f2d83fe8 cb141929 8b080134 (f9400688) > ---[ end trace 0000000000000000 ]--- > ---------------- > Code disassembly (best guess): > 0: 927acd29 and x9, x9, #0x3ffffffffffffc0 > 4: f2d83fe8 movk x8, #0xc1ff, lsl #32 > 8: cb141929 sub x9, x9, x20, lsl #6 > c: 8b080134 add x20, x9, x8 > * 10: f9400688 ldr x8, [x20, #8] <-- trapping instruction > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkal...@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup >
