Subject: KASAN: vmalloc-out-of-bounds Write in pcpu_alloc

From: syzbot <[email-masked]>
Date: Tue, 03 Dec 2019 19:45:07 -0800

Hello,

syzbot found the following crash on:

HEAD commit:    b3c424eb sch_cake: Add missing NLA policy entry TCA_CAKE_S..
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=129c042ae00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7d8ab2e0e09c2a82
dashboard link: https://syzkaller.appspot.com/bug?extid=59b7daa4315e07a994f1
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=140df641e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=147dcc2ae00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

RBP: 00007fff1c60f370 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000003 R14: 00007fff1c60f370 R15: 0000000000000000
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in memset include/linux/string.h:365  
[inline]
BUG: KASAN: vmalloc-out-of-bounds in pcpu_alloc+0x589/0x1380  
mm/percpu.c:1734
Write of size 32768 at addr ffffe8ffff800000 by task syz-executor940/9026

CPU: 1 PID: 9026 Comm: syz-executor940 Not tainted 5.4.0-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+0x197/0x210 lib/dump_stack.c:118
  print_address_description.constprop.0.cold+0x5/0x30b mm/kasan/report.c:374
  __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
  kasan_report+0x12/0x20 mm/kasan/common.c:638
  check_memory_region_inline mm/kasan/generic.c:185 [inline]
  check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
  memset+0x24/0x40 mm/kasan/common.c:107
  memset include/linux/string.h:365 [inline]
  pcpu_alloc+0x589/0x1380 mm/percpu.c:1734
  __alloc_percpu_gfp+0x28/0x30 mm/percpu.c:1783
  prealloc_init kernel/bpf/hashtab.c:154 [inline]
  htab_map_alloc+0xdb9/0x11c0 kernel/bpf/hashtab.c:378
  find_and_alloc_map kernel/bpf/syscall.c:123 [inline]
  map_create kernel/bpf/syscall.c:654 [inline]
  __do_sys_bpf+0x478/0x37b0 kernel/bpf/syscall.c:3012
  __se_sys_bpf kernel/bpf/syscall.c:2989 [inline]
  __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:2989
  do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441b99
Code: e8 ec 03 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 1b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff1c60f318 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441b99
RDX: 000000000000003c RSI: 0000000020000380 RDI: 0000000000000000
RBP: 00007fff1c60f370 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000003 R14: 00007fff1c60f370 R15: 0000000000000000

Memory state around the buggy address:
BUG: unable to handle page fault for address: fffff91fffefffe0
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 21ffe6067 P4D 21ffe6067 PUD aa56b067 PMD aa56c067 PTE 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 9026 Comm: syz-executor940 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:56
Code: cc cc cc cc eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3  
48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 <f3> a4 c3 0f 1f  
80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe
RSP: 0018:ffffc90001fa7990 EFLAGS: 00010082
RAX: ffffc90001fa799c RBX: fffff91fffefffe0 RCX: 0000000000000010
RDX: 0000000000000010 RSI: fffff91fffefffe0 RDI: ffffc90001fa799c
RBP: ffffc90001fa79f0 R08: ffff888091714400 R09: fffff520003f4f38
R10: fffff520003f4f37 R11: ffffc90001fa79be R12: fffff91ffff00000
R13: 0000200000000000 R14: 00000000fffffffe R15: ffff88821fffd100
FS:  0000000000d10880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff91fffefffe0 CR3: 0000000099ba1000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  __kasan_report.cold+0x30/0x41 mm/kasan/report.c:508
  kasan_report+0x12/0x20 mm/kasan/common.c:638
  check_memory_region_inline mm/kasan/generic.c:185 [inline]
  check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
  memset+0x24/0x40 mm/kasan/common.c:107
  memset include/linux/string.h:365 [inline]
  pcpu_alloc+0x589/0x1380 mm/percpu.c:1734
  __alloc_percpu_gfp+0x28/0x30 mm/percpu.c:1783
  prealloc_init kernel/bpf/hashtab.c:154 [inline]
  htab_map_alloc+0xdb9/0x11c0 kernel/bpf/hashtab.c:378
  find_and_alloc_map kernel/bpf/syscall.c:123 [inline]
  map_create kernel/bpf/syscall.c:654 [inline]
  __do_sys_bpf+0x478/0x37b0 kernel/bpf/syscall.c:3012
  __se_sys_bpf kernel/bpf/syscall.c:2989 [inline]
  __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:2989
  do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441b99
Code: e8 ec 03 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 1b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff1c60f318 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441b99
RDX: 000000000000003c RSI: 0000000020000380 RDI: 0000000000000000
RBP: 00007fff1c60f370 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000003 R14: 00007fff1c60f370 R15: 0000000000000000
Modules linked in:
CR2: fffff91fffefffe0
---[ end trace 28e1dfa4887d81a1 ]---
RIP: 0010:memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:56
Code: cc cc cc cc eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3  
48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 <f3> a4 c3 0f 1f  
80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe
RSP: 0018:ffffc90001fa7990 EFLAGS: 00010082
RAX: ffffc90001fa799c RBX: fffff91fffefffe0 RCX: 0000000000000010
RDX: 0000000000000010 RSI: fffff91fffefffe0 RDI: ffffc90001fa799c
RBP: ffffc90001fa79f0 R08: ffff888091714400 R09: fffff520003f4f38
R10: fffff520003f4f37 R11: ffffc90001fa79be R12: fffff91ffff00000
R13: 0000200000000000 R14: 00000000fffffffe R15: ffff88821fffd100
FS:  0000000000d10880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff91fffefffe0 CR3: 0000000099ba1000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

---
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