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    SubjectRe: WARNING in per_cpu_alloc
    Hi,

    On Sun, Oct 15, 2017 at 08:28:55AM -0400, Shankara Pailoor wrote:
    > Hi,
    >
    > We found the warning when fuzzing with Syzkaller on Linux 4-14-rc4.
    >
    > illegal size (32776) or align (8) for percpu allocation
    > ------------[ cut here ]------------
    > WARNING: CPU: 0 PID: 22596 at mm/percpu.c:1365 pcpu_alloc+0x140/0x10f0
    > Kernel panic - not syncing: panic_on_warn set ...

    FWIW, this has already been reported upstream [1]. The suggested fix was
    to make pcpu_alloc suport __GFP_NOWARN, but I haven't had the chance to
    fix that up yet.

    Thanks,
    Mark.

    [1] https://lkml.kernel.org/r/20170928112727.GA11310@leverpostej

    > CPU: 0 PID: 22596 Comm: syz-executor1 Not tainted 4.14.0-rc4 #1
    > Hardware name: Google Google Compute Engine/Google Compute Engine,
    > BIOS Google 01/01/2011
    > Call Trace:
    > dump_stack+0x115/0x1da
    > panic+0x1b4/0x3a7
    > __warn+0x1c4/0x1d9
    > report_bug+0x211/0x2d0
    > fixup_bug+0x40/0x90
    > do_trap+0x260/0x390
    > do_error_trap+0x11c/0x350
    > do_invalid_op+0x1b/0x20
    > invalid_op+0x18/0x20
    > RIP: 0010:pcpu_alloc+0x140/0x10f0
    > RSP: 0018:ffff8800a752f6a8 EFLAGS: 00010286
    > RAX: 0000000000000037 RBX: 0000000000000000 RCX: 0000000000000000
    > RDX: 0000000000000037 RSI: ffffc90001a32000 RDI: ffffed0014ea5ec9
    > RBP: ffff8800a752f920 R08: ffff8800a752ed98 R09: 0000000000000000
    > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000008007
    > R13: 0000000000000000 R14: ffff8800a752fec0 R15: 0000000000000008
    > __alloc_percpu+0x24/0x30
    > dev_map_alloc+0x68e/0xb70
    > SyS_bpf+0xd25/0x4500
    > entry_SYSCALL_64_fastpath+0x1f/0xbe
    > RIP: 0033:0x452349
    > RSP: 002b:00007f8c38897be8 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
    > RAX: ffffffffffffffda RBX: 0000000000968000 RCX: 0000000000452349
    > RDX: 000000000000001c RSI: 0000000020038000 RDI: 0000000000000000
    > RBP: 0000000000000046 R08: 0000000000000000 R09: 0000000000000000
    > R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f25a8
    > R13: 00000000ffffffff R14: 0000000000968070 R15: 0000000000000000
    > Dumping ftrace buffer:
    > (ftrace buffer empty)
    > Kernel Offset: 0x23800000 from 0xffffffff81000000 (relocation range:
    > 0xffffffff80000000-0xffffffffbfffffff)
    > Rebooting in 86400 seconds..
    >
    > Here is the reproducer program: https://pastebin.com/TdSTCu5E
    >
    > --
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