On Sat, May 09, 2020 at 12:20:14AM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: d5eeab8d Merge tag 'scsi-fixes' of git://git.kernel.org/pu.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=15093632100000 > kernel config: https://syzkaller.appspot.com/x/.config?x=b0212dbee046bc1f > dashboard link: https://syzkaller.appspot.com/bug?extid=353be47c9ce21b68b7ed > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > userspace arch: i386 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=168ee02c100000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=119f3788100000 > > The bug was bisected to: > > commit 2bef9aed6f0e22391c8d4570749b1acc9bc3981e > Author: Jeremy Linton <jeremy.linton@xxxxxxx> > Date: Mon May 4 20:13:48 2020 +0000 > > usb: usbfs: correct kernel->user page attribute mismatch > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1701f168100000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=1481f168100000 > console output: https://syzkaller.appspot.com/x/log.txt?x=1081f168100000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+353be47c9ce21b68b7ed@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 2bef9aed6f0e ("usb: usbfs: correct kernel->user page attribute mismatch") > > ------------[ cut here ]------------ > memtype_reserve failed: [mem 0xffffffffff000-0x00008fff], req write-back > WARNING: CPU: 1 PID: 7025 at arch/x86/mm/pat/memtype.c:589 memtype_reserve+0x69f/0x820 arch/x86/mm/pat/memtype.c:589 > Kernel panic - not syncing: panic_on_warn set ... > CPU: 1 PID: 7025 Comm: syz-executor254 Not tainted 5.7.0-rc4-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x188/0x20d lib/dump_stack.c:118 > panic+0x2e3/0x75c kernel/panic.c:221 > __warn.cold+0x2f/0x35 kernel/panic.c:582 > report_bug+0x27b/0x2f0 lib/bug.c:195 > fixup_bug arch/x86/kernel/traps.c:175 [inline] > fixup_bug arch/x86/kernel/traps.c:170 [inline] > do_error_trap+0x12b/0x220 arch/x86/kernel/traps.c:267 > do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:286 > invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 > RIP: 0010:memtype_reserve+0x69f/0x820 arch/x86/mm/pat/memtype.c:589 > Code: 48 8b 2c ed c0 00 29 88 e8 ae ad 3e 00 48 8d 4b ff 49 89 e8 4c 89 e2 48 c7 c6 20 01 29 88 48 c7 c7 80 f9 28 88 e8 79 e8 0f 00 <0f> 0b 41 bf ea ff ff ff e9 03 fc ff ff 41 bf ea ff ff ff e9 f8 fb > RSP: 0018:ffffc900015e7790 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: 0000000000009000 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff815ce181 RDI: fffff520002bcee4 > RBP: ffffffff8828ff40 R08: ffff888097ce85c0 R09: ffffed1015ce45f1 > R10: ffff8880ae722f83 R11: ffffed1015ce45f0 R12: 000ffffffffff000 > R13: 1ffff920002bcef8 R14: dffffc0000000000 R15: 0000000000000000 > reserve_pfn_range+0x173/0x470 arch/x86/mm/pat/memtype.c:941 > track_pfn_remap+0x18b/0x280 arch/x86/mm/pat/memtype.c:1033 > remap_pfn_range+0x202/0xbf0 mm/memory.c:2130 > dma_direct_mmap+0x197/0x260 kernel/dma/direct.c:453 > dma_mmap_attrs+0xfe/0x150 kernel/dma/mapping.c:237 > usbdev_mmap+0x3ae/0x730 drivers/usb/core/devio.c:254 > call_mmap include/linux/fs.h:1912 [inline] > mmap_region+0xafb/0x1540 mm/mmap.c:1772 > do_mmap+0x849/0x1160 mm/mmap.c:1545 > do_mmap_pgoff include/linux/mm.h:2553 [inline] > vm_mmap_pgoff+0x197/0x200 mm/util.c:506 > ksys_mmap_pgoff+0x457/0x5b0 mm/mmap.c:1595 > do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] > do_fast_syscall_32+0x270/0xe90 arch/x86/entry/common.c:396 > entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 > Kernel Offset: disabled > Rebooting in 86400 seconds.. So should memtype_reserve() not do a WARN if given invalid parameters as it can be triggered by userspace requests? A normal "invalid request" debug line is probably all that is needed, right? thanks, greg k-h
