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KMSAN: uninit-value in dev_map_lookup_elem

syzbot syzbot 4 participants 9 messages Mar 25, 2024 – Mar 28, 2024

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author syzbot
#0 lore raw

Hello,

syzbot found the following issue on:

HEAD commit:    5e74df2f8f15 Merge tag 'x86-urgent-2024-03-24' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=148872a5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6bd769cb793b98a
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3cf6f08d68868f9db3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15921a6e180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e081f1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1a82880723a7/disk-5e74df2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd3046ac43b9/vmlinux-5e74df2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2097be59cbc1/bzImage-5e74df2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by [email protected]

=====================================================

BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
 __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
 dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
 ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
 bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
 __bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run include/linux/filter.h:664 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
 bpf_trace_run5+0x16f/0x350 kernel/trace/bpf_trace.c:2423
 __bpf_trace_ext4_remove_blocks+0x45/0x60 include/trace/events/ext4.h:1984
 __traceiter_ext4_remove_blocks+0xb5/0x170 include/trace/events/ext4.h:1984
 trace_ext4_remove_blocks include/trace/events/ext4.h:1984 [inline]
 ext4_remove_blocks fs/ext4/extents.c:2463 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2686 [inline]
 ext4_ext_remove_space+0x4e30/0x7e00 fs/ext4/extents.c:2934
 ext4_ext_truncate+0x1e3/0x390 fs/ext4/extents.c:4440
 ext4_truncate+0x14c6/0x1e10 fs/ext4/inode.c:4146
 ext4_evict_inode+0x1886/0x24d0 fs/ext4/inode.c:258
 evict+0x3ae/0xa60 fs/inode.c:667
 iput_final fs/inode.c:1741 [inline]
 iput+0x9ca/0xe10 fs/inode.c:1767
 d_delete_notify include/linux/fsnotify.h:307 [inline]
 vfs_rmdir+0x53c/0x790 fs/namei.c:4222
 do_rmdir+0x630/0x8b0 fs/namei.c:4268
 __do_sys_rmdir fs/namei.c:4287 [inline]
 __se_sys_rmdir fs/namei.c:4285 [inline]
 __x64_sys_rmdir+0x78/0xb0 fs/namei.c:4285
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Local variable stack created at:

 __bpf_prog_run256+0x45/0xe0 kernel/bpf/core.c:2237
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run include/linux/filter.h:664 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
 bpf_trace_run5+0x16f/0x350 kernel/trace/bpf_trace.c:2423

CPU: 0 PID: 5017 Comm: syz-executor365 Not tainted 6.8.0-syzkaller-13236-g5e74df2f8f15 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
=====================================================

---
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 [email protected].

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

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If you want to undo deduplication, reply with:
#syz undup

#1 lore raw
Quoted 22 lines · syzbot

Hello,

syzbot found the following issue on:

HEAD commit:    5e74df2f8f15 Merge tag 'x86-urgent-2024-03-24' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=148872a5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6bd769cb793b98a
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3cf6f08d68868f9db3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15921a6e180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e081f1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1a82880723a7/disk-5e74df2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd3046ac43b9/vmlinux-5e74df2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2097be59cbc1/bzImage-5e74df2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by [email protected]

=====================================================

Quoted 8 lines
BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
  __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
  dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
  ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
  bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
  ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
  __bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237

It should be in the interpreter mode.

The C reproducer is trying to run the following bpf prog:

0: (18) r0 = 0x0
2: (18) r1 = map[id:49]
4: (b7) r8 = 16777216
5: (7b) *(u64 *)(r10 -8) = r8
6: (bf) r2 = r10
7: (07) r2 += -229

           ^^^^^^^^^^

8: (b7) r3 = 8
9: (b7) r4 = 0
10: (85) call dev_map_lookup_elem#1543472
11: (95) exit

I think this KMSAN report (and a few others related to lookup/delete_elem) should only happen in the interpreter mode.

Does it worth to suppress it by always initializing the stack in the interpreter mode considering the interpreter is not very speed sensitive ?

Quoted 39 lines
  bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
  __bpf_prog_run include/linux/filter.h:657 [inline]
  bpf_prog_run include/linux/filter.h:664 [inline]
  __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
  bpf_trace_run5+0x16f/0x350 kernel/trace/bpf_trace.c:2423
  __bpf_trace_ext4_remove_blocks+0x45/0x60 include/trace/events/ext4.h:1984
  __traceiter_ext4_remove_blocks+0xb5/0x170 include/trace/events/ext4.h:1984
  trace_ext4_remove_blocks include/trace/events/ext4.h:1984 [inline]
  ext4_remove_blocks fs/ext4/extents.c:2463 [inline]
  ext4_ext_rm_leaf fs/ext4/extents.c:2686 [inline]
  ext4_ext_remove_space+0x4e30/0x7e00 fs/ext4/extents.c:2934
  ext4_ext_truncate+0x1e3/0x390 fs/ext4/extents.c:4440
  ext4_truncate+0x14c6/0x1e10 fs/ext4/inode.c:4146
  ext4_evict_inode+0x1886/0x24d0 fs/ext4/inode.c:258
  evict+0x3ae/0xa60 fs/inode.c:667
  iput_final fs/inode.c:1741 [inline]
  iput+0x9ca/0xe10 fs/inode.c:1767
  d_delete_notify include/linux/fsnotify.h:307 [inline]
  vfs_rmdir+0x53c/0x790 fs/namei.c:4222
  do_rmdir+0x630/0x8b0 fs/namei.c:4268
  __do_sys_rmdir fs/namei.c:4287 [inline]
  __se_sys_rmdir fs/namei.c:4285 [inline]
  __x64_sys_rmdir+0x78/0xb0 fs/namei.c:4285
  do_syscall_64+0xd5/0x1f0
  entry_SYSCALL_64_after_hwframe+0x6d/0x75

Local variable stack created at:

  __bpf_prog_run256+0x45/0xe0 kernel/bpf/core.c:2237
  bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
  __bpf_prog_run include/linux/filter.h:657 [inline]
  bpf_prog_run include/linux/filter.h:664 [inline]
  __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
  bpf_trace_run5+0x16f/0x350 kernel/trace/bpf_trace.c:2423

CPU: 0 PID: 5017 Comm: syz-executor365 Not tainted 6.8.0-syzkaller-13236-g5e74df2f8f15 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
=====================================================
#2 lore raw
Quoted 47 lines · Martin KaFai Lau
Quoted 22 lines · syzbot

Hello,

syzbot found the following issue on:

HEAD commit:    5e74df2f8f15 Merge tag 'x86-urgent-2024-03-24' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=148872a5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6bd769cb793b98a
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3cf6f08d68868f9db3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15921a6e180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e081f1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1a82880723a7/disk-5e74df2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd3046ac43b9/vmlinux-5e74df2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2097be59cbc1/bzImage-5e74df2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by [email protected]

=====================================================

Quoted 8 lines
BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
  __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
  dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
  ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
  bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
  ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
  __bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237

It should be in the interpreter mode.

The C reproducer is trying to run the following bpf prog:

    0: (18) r0 = 0x0
    2: (18) r1 = map[id:49]
    4: (b7) r8 = 16777216
    5: (7b) *(u64 *)(r10 -8) = r8
    6: (bf) r2 = r10
    7: (07) r2 += -229
            ^^^^^^^^^^

    8: (b7) r3 = 8
    9: (b7) r4 = 0
Quoted 8 lines

10: (85) call dev_map_lookup_elem#1543472
11: (95) exit

I think this KMSAN report (and a few others related to lookup/delete_elem) should only happen in the interpreter mode.

Does it worth to suppress it by always initializing the stack in the interpreter mode considering the interpreter is not very speed sensitive ?

Maybe we can mark it as initialized from kmsan pov ? There are kasan_poison/unpoison helpers that may fit ?

reviewer
#3 lore raw
Quoted 49 lines · Alexei Starovoitov
Quoted 48 lines · Martin KaFai Lau
Quoted 22 lines · syzbot

Hello,

syzbot found the following issue on:

HEAD commit:    5e74df2f8f15 Merge tag 'x86-urgent-2024-03-24' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=148872a5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6bd769cb793b98a
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3cf6f08d68868f9db3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15921a6e180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e081f1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1a82880723a7/disk-5e74df2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd3046ac43b9/vmlinux-5e74df2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2097be59cbc1/bzImage-5e74df2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by [email protected]

=====================================================

Quoted 8 lines
BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
   __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
   dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
   ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
   bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
   ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
   __bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237

It should be in the interpreter mode.

The C reproducer is trying to run the following bpf prog:

     0: (18) r0 = 0x0
     2: (18) r1 = map[id:49]
     4: (b7) r8 = 16777216
     5: (7b) *(u64 *)(r10 -8) = r8
     6: (bf) r2 = r10
     7: (07) r2 += -229
             ^^^^^^^^^^

     8: (b7) r3 = 8
     9: (b7) r4 = 0
    10: (85) call dev_map_lookup_elem#1543472
    11: (95) exit
Quoted 7 lines
Quoted 5 lines

I think this KMSAN report (and a few others related to lookup/delete_elem) should only happen in the interpreter mode.

Does it worth to suppress it by always initializing the stack in the interpreter mode considering the interpreter is not very speed sensitive ?

Maybe we can mark it as initialized from kmsan pov ? There are kasan_poison/unpoison helpers that may fit ?

Maybe use kmsan_unpoison_memory()?

In lib/Kconfig.kmsan, we have

config KMSAN
bool "KMSAN: detector of uninitialized values use" depends on HAVE_ARCH_KMSAN && HAVE_KMSAN_COMPILER
depends on DEBUG_KERNEL && !KASAN && !KCSAN
depends on !PREEMPT_RT
select STACKDEPOT
select STACKDEPOT_ALWAYS_INIT
help
KernelMemorySanitizer (KMSAN) is a dynamic detector of uses of uninitialized values in the kernel. It is based on compiler instrumentation provided by Clang and thus requires Clang to build.

An important note is that KMSAN is not intended for production use, because it drastically increases kernel memory footprint and slows the whole system down.

See <file:Documentation/dev-tools/kmsan.rst> for more details.

So enable KMSAN, KASAN and KCSAN needs to be disabled.

#4 lore raw
Quoted 54 lines · Yonghong Song
Quoted 52 lines · Alexei Starovoitov
Quoted 51 lines · Martin KaFai Lau
Quoted 22 lines · syzbot

Hello,

syzbot found the following issue on:

HEAD commit:    5e74df2f8f15 Merge tag 'x86-urgent-2024-03-24' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=148872a5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6bd769cb793b98a
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3cf6f08d68868f9db3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15921a6e180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e081f1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1a82880723a7/disk-5e74df2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd3046ac43b9/vmlinux-5e74df2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2097be59cbc1/bzImage-5e74df2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by [email protected]

=====================================================

Quoted 8 lines
BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
   __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
   dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
   ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
   bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
   ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
   __bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237

It should be in the interpreter mode.

The C reproducer is trying to run the following bpf prog:

     0: (18) r0 = 0x0
     2: (18) r1 = map[id:49]
     4: (b7) r8 = 16777216
     5: (7b) *(u64 *)(r10 -8) = r8
     6: (bf) r2 = r10
     7: (07) r2 += -229
             ^^^^^^^^^^

     8: (b7) r3 = 8
     9: (b7) r4 = 0
    10: (85) call dev_map_lookup_elem#1543472
    11: (95) exit

I think this KMSAN report (and a few others related to lookup/delete_elem) should only happen in the interpreter mode.

Quoted 6 lines
Quoted 4 lines
Quoted 2 lines

Does it worth to suppress it by always initializing the stack in the interpreter mode considering the interpreter is not very speed sensitive ?

Maybe we can mark it as initialized from kmsan pov ? There are kasan_poison/unpoison helpers that may fit ?

Maybe use kmsan_unpoison_memory()?

Good idea. It should do. My qemu cannot boot with CONFIG_KMSAN somehow. I will ask syzbot to test.

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/martin.lau/bpf-next.git interpreter.kmsan

author syzbot
#5 lore raw
syzbot tried to test the proposed patch but the build/boot failed:

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

.o

  CC      fs/aio.o
  CC      drivers/hid/hid-gt683r.o
  CC      drivers/hid/hid-gyration.o
  CC      drivers/hid/hid-holtek-kbd.o
  CC      drivers/platform/x86/p2sb.o
  CC      drivers/iio/buffer/industrialio-triggered-buffer.o
  CC      drivers/staging/rtl8712/rtl871x_ioctl_set.o
  CC      drivers/staging/rtl8712/rtl8712_led.o
  AR      drivers/mailbox/built-in.a
  CC      fs/btrfs/uuid-tree.o
  CC      fs/xfs/xfs_dquot.o
  CC      fs/dax.o
  AR      drivers/iio/accel/built-in.a
  AR      drivers/iio/cdc/built-in.a
  CC      fs/locks.o
  CC      drivers/iio/adc/viperboard_adc.o
  CC      drivers/gpu/drm/i915/display/intel_plane_initial.o
  CC      fs/binfmt_misc.o
  CC      fs/binfmt_script.o
  CC      net/netfilter/xt_length.o
  CC      drivers/hid/hid-holtek-mouse.o
  AR      drivers/iio/chemical/built-in.a
  CC      fs/xfs/xfs_dquot_item.o
  AR      drivers/iio/common/cros_ec_sensors/built-in.a
  CC      drivers/iio/common/hid-sensors/hid-sensor-attributes.o
  CC      drivers/extcon/devres.o
  CC      fs/bcachefs/opts.o
  CC      drivers/iio/common/hid-sensors/hid-sensor-trigger.o
  CC      fs/binfmt_elf.o
  AR      drivers/media/usb/pvrusb2/built-in.a
  CC      fs/xfs/xfs_trans_dquot.o
  AR      drivers/iio/common/inv_sensors/built-in.a
  CC      fs/xfs/xfs_qm_syscalls.o
  CC      fs/xfs/xfs_qm_bhv.o
  CC      drivers/staging/rtl8712/rtl871x_mlme.o
  AR      drivers/iio/dac/built-in.a
  CC      drivers/hid/hid-holtekff.o
  CC      drivers/hid/hid-icade.o
  CC      drivers/iio/buffer/kfifo_buf.o
  AR      drivers/iio/common/ms_sensors/built-in.a
  CC      net/netfilter/xt_limit.o
  CC      net/netfilter/xt_mac.o
  AR      drivers/iio/common/scmi_sensors/built-in.a
  CC      drivers/thunderbolt/nhi.o
  AR      drivers/hwtracing/intel_th/built-in.a
  AR      drivers/iio/adc/built-in.a
  CC      net/netfilter/xt_multiport.o
  AR      drivers/iio/common/ssp_sensors/built-in.a
  CC      drivers/gpu/drm/i915/display/intel_pmdemand.o
  AR      drivers/iio/dummy/built-in.a
  CC      drivers/thunderbolt/nhi_ops.o
  CC      fs/btrfs/props.o
  AR      drivers/iio/common/st_sensors/built-in.a
  CC      net/netfilter/xt_nfacct.o
  CC      fs/xfs/xfs_qm.o
  CC      net/netfilter/xt_osf.o
  AR      drivers/platform/x86/built-in.a
  CC      fs/xfs/xfs_quotaops.o
  AR      drivers/platform/built-in.a
  CC      fs/xfs/xfs_rtalloc.o
  CC      drivers/android/binderfs.o
  CC      drivers/iio/gyro/hid-sensor-gyro-3d.o
  CC      drivers/extcon/extcon-intel-cht-wc.o
  CC      fs/compat_binfmt_elf.o
  CC      fs/xfs/xfs_acl.o
  CC      drivers/thunderbolt/ctl.o
  CC      drivers/thunderbolt/tb.o
  CC      fs/btrfs/free-space-tree.o
  CC      fs/btrfs/tree-checker.o
  CC      fs/xfs/xfs_sysctl.o
  CC      drivers/hid/hid-ite.o
  CC      drivers/staging/rtl8712/ieee80211.o
  CC      drivers/staging/rtl8712/rtl871x_mp_ioctl.o
  CC      drivers/staging/rtl8712/rtl871x_mp.o
  CC      fs/btrfs/space-info.o
  CC      drivers/thunderbolt/switch.o
  CC      net/netfilter/xt_owner.o
  CC      drivers/hid/hid-kensington.o
  AR      drivers/nvmem/layouts/built-in.a
  CC      drivers/nvmem/core.o
  CC      drivers/staging/rtl8712/mlme_linux.o
  CC      fs/backing-file.o
  CC      drivers/staging/rtl8712/recv_linux.o
  CC      drivers/staging/rtl8712/xmit_linux.o
  CC      drivers/thunderbolt/cap.o
  CC      fs/bcachefs/printbuf.o
  AR      drivers/ras/built-in.a
  CC      fs/mbcache.o
  AR      drivers/iio/filter/built-in.a
  CC      drivers/counter/counter-core.o
  AR      drivers/iio/buffer/built-in.a
  CC      fs/posix_acl.o
  CC      drivers/staging/rtl8712/usb_intf.o
  CC      fs/coredump.o
  AR      drivers/iio/frequency/built-in.a
  AR      drivers/iio/health/built-in.a
  CC      drivers/most/core.o
  AR      drivers/extcon/built-in.a
  CC      drivers/counter/counter-sysfs.o
  CC      drivers/counter/counter-chrdev.o
  CC      net/netfilter/xt_cgroup.o
  AR      drivers/iio/gyro/built-in.a
  AR      drivers/iio/common/hid-sensors/built-in.a
  CC      fs/drop_caches.o
  AR      drivers/iio/common/built-in.a
  CC      drivers/iio/humidity/hid-sensor-humidity.o
  CC      fs/sysctls.o
  CC      drivers/hid/hid-keytouch.o
  CC      fs/xfs/xfs_ioctl32.o
  CC      drivers/thunderbolt/path.o
  CC      drivers/thunderbolt/tunnel.o
  AR      fs/ocfs2/built-in.a
  CC      drivers/thunderbolt/eeprom.o
  CC      net/netfilter/xt_physdev.o
  CC      fs/fhandle.o
  CC      drivers/android/binder.o
  CC      drivers/staging/rtl8712/os_intfs.o
  CC      fs/btrfs/block-rsv.o
  CC      drivers/android/binder_alloc.o
  CC      drivers/hid/hid-kye.o
  CC      drivers/most/configfs.o
  AR      drivers/iio/imu/bmi160/built-in.a
  AR      drivers/iio/imu/bmi323/built-in.a
  AR      drivers/iio/imu/bno055/built-in.a
  CC      fs/bcachefs/quota.o
  CC      drivers/iio/light/hid-sensor-als.o
  CC      drivers/iio/light/hid-sensor-prox.o
  AR      drivers/iio/imu/inv_icm42600/built-in.a
  AR      drivers/iio/imu/inv_mpu6050/built-in.a
  CC      fs/btrfs/delalloc-space.o
  AR      drivers/iio/imu/st_lsm6dsx/built-in.a
  CC      fs/btrfs/block-group.o
  AR      drivers/iio/imu/st_lsm9ds0/built-in.a
  CC      fs/btrfs/discard.o
  AR      drivers/iio/imu/built-in.a
  CC      fs/btrfs/reflink.o
  CC      drivers/staging/rtl8712/rtl871x_pwrctrl.o
  CC      fs/bcachefs/rebalance.o
  CC      drivers/iio/magnetometer/hid-sensor-magn-3d.o
  CC      fs/btrfs/subpage.o
  CC      drivers/thunderbolt/domain.o
  CC      fs/btrfs/tree-mod-log.o
  CC      net/netfilter/xt_pkttype.o
  CC      fs/btrfs/extent-io-tree.o
  AR      drivers/iio/multiplexer/built-in.a
  CC      drivers/iio/orientation/hid-sensor-incl-3d.o
  CC      drivers/gpu/drm/i915/display/intel_psr.o
  AR      drivers/media/usb/gspca/built-in.a
  AR      drivers/iio/position/built-in.a
  CC      drivers/iio/orientation/hid-sensor-rotation.o
  AR      drivers/media/usb/built-in.a
  CC      net/netfilter/xt_policy.o
  CC      net/netfilter/xt_quota.o
  AR      drivers/iio/potentiometer/built-in.a
  CC      drivers/nvmem/layouts.o
  CC      drivers/staging/rtl8712/rtl8712_recv.o
  AR      drivers/media/built-in.a
  CC      fs/bcachefs/recovery.o
  CC      fs/xfs/xfs_pnfs.o
  CC      drivers/gpu/drm/i915/display/intel_quirks.o
  CC      fs/btrfs/fs.o
  AR      drivers/iio/potentiostat/built-in.a
  CC      drivers/hid/hid-lcpower.o
  CC      drivers/hid/hid-lenovo.o
  CC      drivers/hid/hid-lg.o
  CC      drivers/hid/hid-lgff.o
  AR      drivers/iio/humidity/built-in.a
  CC      net/netfilter/xt_rateest.o
  AR      drivers/iio/resolver/built-in.a
  AR      drivers/iio/proximity/built-in.a
  CC      drivers/gpu/drm/i915/display/intel_sprite.o
  CC      drivers/iio/pressure/hid-sensor-press.o
  CC      drivers/iio/temperature/hid-sensor-temperature.o
  CC      drivers/gpu/drm/i915/display/intel_sprite_uapi.o
  CC      fs/btrfs/messages.o
  CC      drivers/gpu/drm/i915/display/intel_tc.o
  AR      drivers/counter/built-in.a
  CC      drivers/gpu/drm/i915/display/intel_vblank.o
  CC      drivers/gpu/drm/i915/display/intel_vga.o
  CC      drivers/hid/hid-lg2ff.o
  CC      drivers/thunderbolt/dma_port.o
  CC      fs/btrfs/bio.o
  AR      drivers/iio/light/built-in.a
  AR      drivers/iio/test/built-in.a
  AR      drivers/iio/trigger/built-in.a
  CC      drivers/thunderbolt/icm.o
  CC      net/netfilter/xt_realm.o
  CC      net/netfilter/xt_recent.o
  CC      net/netfilter/xt_sctp.o
  CC      drivers/thunderbolt/property.o
  AR      drivers/iio/magnetometer/built-in.a
  CC      drivers/hid/hid-lg3ff.o
  AR      drivers/most/built-in.a
  CC      drivers/thunderbolt/xdomain.o
  CC      drivers/hid/hid-lg4ff.o
  CC      net/netfilter/xt_socket.o
  CC      drivers/thunderbolt/lc.o
  CC      net/netfilter/xt_state.o
  CC      drivers/hid/hid-lg-g15.o
  CC      fs/btrfs/lru_cache.o
  CC      drivers/staging/rtl8712/rtl871x_recv.o
  CC      drivers/iio/industrialio-core.o
  CC      drivers/gpu/drm/i915/display/intel_wm.o
  AR      drivers/iio/orientation/built-in.a
  CC      net/netfilter/xt_statistic.o
  CC      drivers/iio/industrialio-event.o
  CC      drivers/iio/inkern.o
  CC      net/netfilter/xt_string.o
  CC      fs/btrfs/raid-stripe-tree.o
  CC      net/netfilter/xt_tcpmss.o
  CC      net/netfilter/xt_time.o
  CC      drivers/iio/industrialio-buffer.o
  CC      drivers/hid/hid-logitech-dj.o
  CC      drivers/gpu/drm/i915/display/skl_scaler.o
  AR      drivers/nvmem/built-in.a
  CC      drivers/iio/industrialio-trigger.o
  CC      drivers/gpu/drm/i915/display/skl_universal_plane.o
  CC      drivers/thunderbolt/tmu.o
  AR      drivers/iio/temperature/built-in.a
  CC      fs/btrfs/acl.o
  CC      drivers/hid/hid-logitech-hidpp.o
  CC      drivers/hid/hid-magicmouse.o
  AR      drivers/iio/pressure/built-in.a
  CC      drivers/thunderbolt/usb4.o
  CC      drivers/thunderbolt/usb4_port.o
  CC      drivers/staging/rtl8712/rtl871x_sta_mgt.o
  CC      drivers/gpu/drm/i915/display/skl_watermark.o
  CC      drivers/hid/hid-mf.o
  CC      net/netfilter/xt_u32.o
  CC      fs/bcachefs/reflink.o
  CC      drivers/staging/rtl8712/rtl871x_xmit.o
  CC      fs/btrfs/ref-verify.o
  CC      drivers/thunderbolt/nvm.o
  CC      net/netfilter/nf_hooks_lwtunnel.o
  CC      drivers/staging/rtl8712/rtl8712_xmit.o
  CC      fs/bcachefs/sb-clean.o
  CC      drivers/hid/hid-microsoft.o
  CC      fs/bcachefs/replicas.o
  CC      fs/btrfs/zoned.o
  CC      drivers/gpu/drm/i915/display/intel_acpi.o
  CC      fs/bcachefs/sb-counters.o
  CC      drivers/hid/hid-monterey.o
  CC      drivers/gpu/drm/i915/display/intel_opregion.o
  CC      fs/btrfs/verity.o
  CC      fs/bcachefs/sb-downgrade.o
  CC      fs/bcachefs/sb-errors.o
  CC      fs/bcachefs/sb-members.o
  CC      fs/bcachefs/siphash.o
  CC      drivers/hid/hid-multitouch.o
  CC      drivers/hid/hid-nti.o
  CC      drivers/hid/hid-ntrig.o
  CC      drivers/gpu/drm/i915/display/intel_fbdev.o
  CC      drivers/thunderbolt/retimer.o
  CC      fs/bcachefs/six.o
  CC      fs/bcachefs/snapshot.o
  CC      drivers/thunderbolt/quirks.o
  CC      drivers/thunderbolt/clx.o
  CC      drivers/thunderbolt/acpi.o
  CC      drivers/hid/hid-ortek.o
  CC      drivers/hid/hid-prodikeys.o
  CC      drivers/hid/hid-pl.o
  CC      drivers/gpu/drm/i915/display/intel_fbdev_fb.o
  CC      drivers/hid/hid-penmount.o
  CC      drivers/thunderbolt/debugfs.o
  CC      drivers/hid/hid-petalynx.o
  CC      drivers/hid/hid-picolcd_core.o
  CC      drivers/hid/hid-picolcd_fb.o
  CC      drivers/hid/hid-picolcd_backlight.o
  CC      drivers/hid/hid-picolcd_lcd.o
  CC      drivers/gpu/drm/i915/display/intel_display_debugfs.o
  CC      drivers/gpu/drm/i915/display/intel_display_debugfs_params.o
  CC      drivers/hid/hid-picolcd_leds.o
  CC      drivers/gpu/drm/i915/display/intel_pipe_crc.o
  CC      drivers/hid/hid-picolcd_cir.o
  CC      drivers/gpu/drm/i915/display/dvo_ch7017.o
  CC      drivers/gpu/drm/i915/display/dvo_ch7xxx.o
  CC      drivers/hid/hid-picolcd_debugfs.o
  CC      drivers/gpu/drm/i915/display/dvo_ivch.o
  CC      fs/bcachefs/subvolume.o
  CC      fs/bcachefs/super.o
  CC      fs/bcachefs/super-io.o
  CC      fs/bcachefs/sysfs.o
  CC      drivers/hid/hid-plantronics.o
  CC      fs/bcachefs/tests.o
  CC      fs/bcachefs/time_stats.o
  CC      fs/bcachefs/thread_with_file.o
  CC      drivers/hid/hid-primax.o
  CC      fs/bcachefs/trace.o
  CC      drivers/hid/hid-redragon.o
  CC      drivers/hid/hid-retrode.o
  CC      drivers/hid/hid-roccat.o
  CC      drivers/hid/hid-roccat-common.o
  CC      fs/bcachefs/two_state_shared_lock.o
  CC      drivers/hid/hid-roccat-arvo.o
  CC      fs/bcachefs/util.o
  CC      fs/bcachefs/varint.o
  CC      drivers/hid/hid-roccat-isku.o
  CC      drivers/gpu/drm/i915/display/dvo_ns2501.o
  CC      drivers/hid/hid-roccat-kone.o
  CC      fs/bcachefs/xattr.o
  CC      drivers/hid/hid-roccat-koneplus.o
  CC      drivers/gpu/drm/i915/display/dvo_sil164.o
  CC      drivers/hid/hid-roccat-konepure.o
  CC      drivers/hid/hid-roccat-kovaplus.o
  CC      drivers/gpu/drm/i915/display/dvo_tfp410.o
  CC      drivers/gpu/drm/i915/display/g4x_dp.o
  AR      drivers/iio/built-in.a
  AR      drivers/staging/rtl8712/built-in.a
  CC      drivers/hid/hid-roccat-lua.o
  CC      drivers/gpu/drm/i915/display/g4x_hdmi.o
  AR      drivers/staging/built-in.a
  CC      drivers/hid/hid-roccat-pyra.o
  CC      drivers/hid/hid-roccat-ryos.o
  CC      drivers/hid/hid-roccat-savu.o
  AR      net/netfilter/built-in.a
  CC      drivers/hid/hid-rmi.o
  CC      drivers/gpu/drm/i915/display/icl_dsi.o
  CC      drivers/hid/hid-saitek.o
  AR      fs/xfs/built-in.a
  CC      drivers/hid/hid-samsung.o
  AR      net/built-in.a
  CC      drivers/hid/hid-sjoy.o
  CC      drivers/hid/hid-sony.o
  CC      drivers/hid/hid-speedlink.o
  CC      drivers/hid/hid-steelseries.o
  CC      drivers/gpu/drm/i915/display/intel_backlight.o
  CC      drivers/hid/hid-sunplus.o
  CC      drivers/gpu/drm/i915/display/intel_crt.o
  CC      drivers/gpu/drm/i915/display/intel_cx0_phy.o
  CC      drivers/hid/hid-gaff.o
  CC      drivers/hid/hid-tmff.o
  CC      drivers/hid/hid-thrustmaster.o
  CC      drivers/gpu/drm/i915/display/intel_ddi.o
  CC      drivers/hid/hid-tivo.o
  CC      drivers/gpu/drm/i915/display/intel_ddi_buf_trans.o
  CC      drivers/hid/hid-topseed.o
  CC      drivers/hid/hid-twinhan.o
  CC      drivers/hid/hid-uclogic-core.o
  CC      drivers/hid/hid-uclogic-rdesc.o
  CC      drivers/hid/hid-uclogic-params.o
  AR      drivers/thunderbolt/built-in.a
  CC      drivers/hid/hid-udraw-ps3.o
  CC      drivers/hid/hid-led.o
  CC      drivers/hid/hid-xinmo.o
  CC      drivers/hid/hid-zpff.o
  CC      drivers/hid/hid-zydacron.o
  CC      drivers/hid/wacom_wac.o
  CC      drivers/hid/wacom_sys.o
  CC      drivers/hid/hid-waltop.o
  CC      drivers/hid/hid-wiimote-core.o
  CC      drivers/hid/hid-wiimote-modules.o
  CC      drivers/hid/hid-wiimote-debug.o
  CC      drivers/hid/hid-sensor-hub.o
  CC      drivers/gpu/drm/i915/display/intel_display_device.o
  CC      drivers/hid/hid-sensor-custom.o
  CC      drivers/gpu/drm/i915/display/intel_display_trace.o
  CC      drivers/gpu/drm/i915/display/intel_dkl_phy.o
  CC      drivers/gpu/drm/i915/display/intel_dp.o
  CC      drivers/gpu/drm/i915/display/intel_dp_aux.o
  CC      drivers/gpu/drm/i915/display/intel_dp_aux_backlight.o
  CC      drivers/gpu/drm/i915/display/intel_dp_hdcp.o
  CC      drivers/gpu/drm/i915/display/intel_dp_link_training.o
  CC      drivers/gpu/drm/i915/display/intel_dp_mst.o
  CC      drivers/gpu/drm/i915/display/intel_dsi.o
  CC      drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.o
  CC      drivers/gpu/drm/i915/display/intel_dsi_vbt.o
  CC      drivers/gpu/drm/i915/display/intel_gmbus.o
  CC      drivers/gpu/drm/i915/display/intel_dvo.o
  CC      drivers/gpu/drm/i915/display/intel_hdmi.o
  CC      drivers/gpu/drm/i915/display/intel_lspcon.o
  CC      drivers/gpu/drm/i915/display/intel_lvds.o
  CC      drivers/gpu/drm/i915/display/intel_panel.o
  CC      drivers/gpu/drm/i915/display/intel_pps.o
  CC      drivers/gpu/drm/i915/display/intel_qp_tables.o
  CC      drivers/gpu/drm/i915/display/intel_sdvo.o
  CC      drivers/gpu/drm/i915/display/intel_snps_phy.o
  CC      drivers/gpu/drm/i915/display/intel_tv.o
  CC      drivers/gpu/drm/i915/display/intel_vdsc.o
  CC      drivers/gpu/drm/i915/display/vlv_dsi.o
  CC      drivers/gpu/drm/i915/display/intel_vrr.o
  CC      drivers/gpu/drm/i915/display/vlv_dsi_pll.o
  CC      drivers/gpu/drm/i915/display/intel_dp_tunnel.o
  AR      fs/btrfs/built-in.a
  CC      drivers/gpu/drm/i915/i915_perf.o
  CC      drivers/gpu/drm/i915/pxp/intel_pxp.o
  CC      drivers/gpu/drm/i915/pxp/intel_pxp_huc.o
  CC      drivers/gpu/drm/i915/pxp/intel_pxp_tee.o
  CC      drivers/gpu/drm/i915/i915_gpu_error.o
  CC      drivers/gpu/drm/i915/i915_vgpu.o
  AR      drivers/android/built-in.a
  AR      fs/bcachefs/built-in.a
  AR      fs/built-in.a
  AR      drivers/hid/built-in.a
  AR      drivers/gpu/drm/i915/built-in.a
  AR      drivers/gpu/drm/built-in.a
  AR      drivers/gpu/built-in.a
  AR      drivers/built-in.a
  AR      built-in.a
  AR      vmlinux.a
  LD      vmlinux.o

Killed
make[2]: *** [scripts/Makefile.vmlinux_o:62: vmlinux.o] Error 137 make[2]: *** Deleting file 'vmlinux.o'
make[1]: *** [/syzkaller/jobs/linux/kernel/Makefile:1141: vmlinux_o] Error 2
make: *** [Makefile:240: __sub-make] Error 2

Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=12986595180000

Tested on:

commit:         d8889e86 bpf: Mark bpf prog stack with kmsan_unposion_..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/martin.lau/bpf-next.git interpreter.kmsan
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6bd769cb793b98a
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3cf6f08d68868f9db3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.

#6 lore raw
Quoted 5 lines · syzbot

Killed
make[2]: *** [scripts/Makefile.vmlinux_o:62: vmlinux.o] Error 137 make[2]: *** Deleting file 'vmlinux.o'
make[1]: *** [/syzkaller/jobs/linux/kernel/Makefile:1141: vmlinux_o] Error 2
make: *** [Makefile:240: __sub-make] Error 2

My second syzbot test attempt passed the build stage and passed the reproducer also. https://lore.kernel.org/all/[email protected]/

Not sure what caused the syzbot build error in the first attempt but should be unrelated to the fix. I will post the patch.

author syzbot
#7 lore raw
In reply to syzbot
For archival purposes, forwarding an incoming command email to [email protected].

For archival purposes, forwarding an incoming command email to [email protected].

***

Subject: Re: [syzbot] [bpf?] [net?] KMSAN: uninit-value in dev_map_lookup_elem
Author: [email protected]

Quoted 88 lines · syzbot

Hello,

syzbot found the following issue on:

HEAD commit:    5e74df2f8f15 Merge tag 'x86-urgent-2024-03-24' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=148872a5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6bd769cb793b98a
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3cf6f08d68868f9db3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15921a6e180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e081f1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1a82880723a7/disk-5e74df2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd3046ac43b9/vmlinux-5e74df2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2097be59cbc1/bzImage-5e74df2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by [email protected]

=====================================================

BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
  __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
  dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
  ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
  bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
  ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
  __bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237
  bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
  __bpf_prog_run include/linux/filter.h:657 [inline]
  bpf_prog_run include/linux/filter.h:664 [inline]
  __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
  bpf_trace_run5+0x16f/0x350 kernel/trace/bpf_trace.c:2423
  __bpf_trace_ext4_remove_blocks+0x45/0x60 include/trace/events/ext4.h:1984
  __traceiter_ext4_remove_blocks+0xb5/0x170 include/trace/events/ext4.h:1984
  trace_ext4_remove_blocks include/trace/events/ext4.h:1984 [inline]
  ext4_remove_blocks fs/ext4/extents.c:2463 [inline]
  ext4_ext_rm_leaf fs/ext4/extents.c:2686 [inline]
  ext4_ext_remove_space+0x4e30/0x7e00 fs/ext4/extents.c:2934
  ext4_ext_truncate+0x1e3/0x390 fs/ext4/extents.c:4440
  ext4_truncate+0x14c6/0x1e10 fs/ext4/inode.c:4146
  ext4_evict_inode+0x1886/0x24d0 fs/ext4/inode.c:258
  evict+0x3ae/0xa60 fs/inode.c:667
  iput_final fs/inode.c:1741 [inline]
  iput+0x9ca/0xe10 fs/inode.c:1767
  d_delete_notify include/linux/fsnotify.h:307 [inline]
  vfs_rmdir+0x53c/0x790 fs/namei.c:4222
  do_rmdir+0x630/0x8b0 fs/namei.c:4268
  __do_sys_rmdir fs/namei.c:4287 [inline]
  __se_sys_rmdir fs/namei.c:4285 [inline]
  __x64_sys_rmdir+0x78/0xb0 fs/namei.c:4285
  do_syscall_64+0xd5/0x1f0
  entry_SYSCALL_64_after_hwframe+0x6d/0x75

Local variable stack created at:

  __bpf_prog_run256+0x45/0xe0 kernel/bpf/core.c:2237
  bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
  __bpf_prog_run include/linux/filter.h:657 [inline]
  bpf_prog_run include/linux/filter.h:664 [inline]
  __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
  bpf_trace_run5+0x16f/0x350 kernel/trace/bpf_trace.c:2423

CPU: 0 PID: 5017 Comm: syz-executor365 Not tainted 6.8.0-syzkaller-13236-g5e74df2f8f15 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
=====================================================

---
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If the report is already addressed, let syzbot know by replying with:
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Quoted 6 lines

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#syz undup

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/martin.lau/bpf-next.git interpreter.kmsan

author syzbot
#8 lore raw
In reply to syzbot
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For archival purposes, forwarding an incoming command email to [email protected].

***

Subject: Re: [syzbot] [bpf?] [net?] KMSAN: uninit-value in dev_map_lookup_elem
Author: [email protected]

Quoted 88 lines · syzbot

Hello,

syzbot found the following issue on:

HEAD commit:    5e74df2f8f15 Merge tag 'x86-urgent-2024-03-24' of git://gi..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=148872a5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6bd769cb793b98a
dashboard link: https://syzkaller.appspot.com/bug?extid=1a3cf6f08d68868f9db3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15921a6e180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e081f1180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1a82880723a7/disk-5e74df2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd3046ac43b9/vmlinux-5e74df2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2097be59cbc1/bzImage-5e74df2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by [email protected]

=====================================================

BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
  __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
  dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
  ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
  bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
  ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
  __bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237
  bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
  __bpf_prog_run include/linux/filter.h:657 [inline]
  bpf_prog_run include/linux/filter.h:664 [inline]
  __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
  bpf_trace_run5+0x16f/0x350 kernel/trace/bpf_trace.c:2423
  __bpf_trace_ext4_remove_blocks+0x45/0x60 include/trace/events/ext4.h:1984
  __traceiter_ext4_remove_blocks+0xb5/0x170 include/trace/events/ext4.h:1984
  trace_ext4_remove_blocks include/trace/events/ext4.h:1984 [inline]
  ext4_remove_blocks fs/ext4/extents.c:2463 [inline]
  ext4_ext_rm_leaf fs/ext4/extents.c:2686 [inline]
  ext4_ext_remove_space+0x4e30/0x7e00 fs/ext4/extents.c:2934
  ext4_ext_truncate+0x1e3/0x390 fs/ext4/extents.c:4440
  ext4_truncate+0x14c6/0x1e10 fs/ext4/inode.c:4146
  ext4_evict_inode+0x1886/0x24d0 fs/ext4/inode.c:258
  evict+0x3ae/0xa60 fs/inode.c:667
  iput_final fs/inode.c:1741 [inline]
  iput+0x9ca/0xe10 fs/inode.c:1767
  d_delete_notify include/linux/fsnotify.h:307 [inline]
  vfs_rmdir+0x53c/0x790 fs/namei.c:4222
  do_rmdir+0x630/0x8b0 fs/namei.c:4268
  __do_sys_rmdir fs/namei.c:4287 [inline]
  __se_sys_rmdir fs/namei.c:4285 [inline]
  __x64_sys_rmdir+0x78/0xb0 fs/namei.c:4285
  do_syscall_64+0xd5/0x1f0
  entry_SYSCALL_64_after_hwframe+0x6d/0x75

Local variable stack created at:

  __bpf_prog_run256+0x45/0xe0 kernel/bpf/core.c:2237
  bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
  __bpf_prog_run include/linux/filter.h:657 [inline]
  bpf_prog_run include/linux/filter.h:664 [inline]
  __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
  bpf_trace_run5+0x16f/0x350 kernel/trace/bpf_trace.c:2423

CPU: 0 PID: 5017 Comm: syz-executor365 Not tainted 6.8.0-syzkaller-13236-g5e74df2f8f15 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
=====================================================

---
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 [email protected].

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 syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

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)

Quoted 6 lines

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

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/martin.lau/bpf-next.git d8889e866be3