Re: [syzbot] KASAN: use-after-free Read in kernfs_add_one

syzbot
2022-10-23T02:53:37Z

Hello,

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

che: Netfs 'afs' registered for caching
[ 13.500882][ T1] Btrfs loaded, crc32c=crc32c-intel, assert=on, zoned=yes, fsverity=yes
[ 13.510556][ T1] Key type big_key registered
[ 13.519302][ T1] Key type encrypted registered
[ 13.524584][ T1] ima: No TPM chip found, activating TPM-bypass!
[ 13.530967][ T1] Loading compiled-in module X.509 certificates
[ 13.538472][ T1] Loaded X.509 cert 'Build time autogenerated kernel key: f850c787ad998c396ae089c083b940ff0a9abb77'
[ 13.549867][ T1] ima: Allocated hash algorithm: sha256
[ 13.555945][ T1] ima: No architecture policies found
[ 13.561723][ T1] evm: Initialising EVM extended attributes:
[ 13.568162][ T1] evm: security.selinux (disabled)
[ 13.573567][ T1] evm: security.SMACK64
[ 13.578111][ T1] evm: security.SMACK64EXEC
[ 13.582752][ T1] evm: security.SMACK64TRANSMUTE
[ 13.588073][ T1] evm: security.SMACK64MMAP
[ 13.592999][ T1] evm: security.apparmor (disabled)
[ 13.598532][ T1] evm: security.ima
[ 13.602464][ T1] evm: security.capability
[ 13.607225][ T1] evm: HMAC attrs: 0x1
[ 13.699721][ T1] PM: Magic number: 10:646:713
[ 13.705725][ T1] video4linux radio24: hash matches
[ 13.716160][ T1] printk: console [netcon0] enabled
[ 13.721404][ T1] netconsole: network logging started
[ 13.727580][ T1] gtp: GTP module loaded (pdp ctx size 104 bytes)
[ 13.737077][ T1] rdma_rxe: loaded
[ 13.741304][ T1] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[ 13.753006][ T1] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[ 13.763068][ T1] ALSA device list:
[ 13.764341][ T7] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[ 13.767026][ T1] #0: Dummy 1
[ 13.776574][ T7] platform regulatory.0: Falling back to sysfs fallback for: regulatory.db
[ 13.788911][ T1] #1: Loopback 1
[ 13.792729][ T1] #2: Virtual MIDI Card 1
[ 13.800826][ T1] md: Waiting for all devices to be available before autodetect
[ 13.808606][ T1] md: If you don't use raid, use raid=noautodetect
[ 13.815242][ T1] md: Autodetecting RAID arrays.
[ 13.820269][ T1] md: autorun ...
[ 13.823994][ T1] md: ... autorun DONE.
[ 13.853970][ T1] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[ 13.864437][ T1] VFS: Mounted root (ext4 filesystem) readonly on device 8:1.
[ 13.886509][ T1] devtmpfs: mounted
[ 13.949731][ T1] Freeing unused kernel image (initmem) memory: 3828K
[ 13.956753][ T1] Write protecting the kernel read-only data: 167936k
[ 13.969087][ T1] Freeing unused kernel image (text/rodata gap) memory: 2012K
[ 13.979387][ T1] Freeing unused kernel image (rodata/data gap) memory: 1688K
[ 13.992266][ T1] Failed to set sysctl parameter 'max_rcu_stall_to_panic=1': parameter not found
[ 14.002382][ T1] Run /sbin/init as init process
[ 14.257070][ T2936] mount (2936) used greatest stack depth: 23376 bytes left
[ 14.317912][ T2937] EXT4-fs (sda1): re-mounted. Opts: (null). Quota mode: none.
[ 14.357277][ T2939] mkdir (2939) used greatest stack depth: 23296 bytes left
mount: mounting selinuxfs on /sys/fs/selinux failed: No such file or directory
mount: mounting mqueue on /dev/mqueue failed: No such file or directory
mount: [ 14.406166][ T2940] mount (2940) used greatest stack depth: 21664 bytes left
mounting hugetlbfs on /dev/hugepages failed: No such file or directory
mount: mounting fuse.lxcfs on /var/lib/lxcfs failed: No such file or directory
Starting syslogd: OK
Starting acpid: OK
Starting klogd: OK
Running sysctl: OK
[ 14.952768][ T2965] logger (2965) used greatest stack depth: 21264 bytes left
Populating /dev using udev: [ 15.122458][ T2969] udevd[2969]: starting version 3.2.10
[ 15.431463][ T2970] udevd[2970]: starting eudev-3.2.10
[ 15.433624][ T2969] udevd (2969) used greatest stack depth: 19776 bytes left
[ 18.456577][ T2979] ================================================================================
[ 18.469857][ T2979] UBSAN: null-ptr-deref in ./include/linux/pagemap.h:1088:17
[ 18.538074][ T2979] member access within null pointer of type 'struct folio'
[ 18.575904][ T2979] CPU: 0 PID: 2979 Comm: udevd Not tainted 5.16.0-rc3-syzkaller-01043-g1a2fb220edca-dirty #0
[ 18.586314][ T2979] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
[ 18.596595][ T2979] Call Trace:
[ 18.599900][ T2979] <TASK>
[ 18.602840][ T2979] dump_stack_lvl+0x1e3/0x2cb
[ 18.607653][ T2979] ? bfq_pos_tree_add_move+0x451/0x451
[ 18.613136][ T2979] ? panic+0x7e3/0x7e3
[ 18.617406][ T2979] ? mpage_readahead+0x6a0/0x6a0
[ 18.622367][ T2979] ubsan_type_mismatch_common+0x280/0x390
[ 18.628692][ T2979] __ubsan_handle_type_mismatch_v1+0x4a/0x60
[ 18.634794][ T2979] mpage_readahead+0x588/0x6a0
[ 18.639606][ T2979] ? dio_await_one+0x250/0x250
[ 18.644440][ T2979] ? blkdev_fallocate+0x330/0x330
[ 18.649751][ T2979] ? put_page+0x90/0x90
[ 18.654283][ T2979] ? __alloc_pages+0x2fd/0x5f0
[ 18.659256][ T2979] ? blk_start_plug_nr_ios+0xaa/0x210
[ 18.664788][ T2979] read_pages+0x162/0x520
[ 18.669173][ T2979] ? page_cache_ra_unbounded+0x840/0x840
[ 18.674829][ T2979] ? filemap_add_folio+0x1ab/0x220
[ 18.680150][ T2979] ? add_to_page_cache_locked+0x90/0x90
[ 18.685994][ T2979] ? folio_alloc+0x47/0x50
[ 18.690543][ T2979] ? filemap_alloc_folio+0x1a9/0x1c0
[ 18.696205][ T2979] page_cache_ra_unbounded+0x6c1/0x840
[ 18.701964][ T2979] ? read_cache_pages_invalidate_pages+0xa0/0xa0
[ 18.708384][ T2979] ? do_page_cache_ra+0xde/0x100
[ 18.713352][ T2979] force_page_cache_ra+0x288/0x2e0
[ 18.718608][ T2979] filemap_read+0x809/0x23d0
[ 18.723270][ T2979] ? find_get_pages_range_tag+0x570/0x570
[ 18.729098][ T2979] ? memset+0x1f/0x40
[ 18.733162][ T2979] ? generic_file_read_iter+0x9e/0x4a0
[ 18.739180][ T2979] ? memset+0x1f/0x40
[ 18.743347][ T2979] ? init_sync_kiocb+0x303/0x4b0
[ 18.748408][ T2979] vfs_read+0x5cd/0x760
[ 18.753197][ T2979] ? kernel_read+0x1f0/0x1f0
[ 18.757837][ T2979] ? __fget_light+0xcc/0x170
[ 18.762803][ T2979] ksys_read+0x19f/0x2d0
[ 18.767273][ T2979] ? vfs_write+0x720/0x720
[ 18.771729][ T2979] ? syscall_enter_from_user_mode+0x2e/0x1c0
[ 18.777991][ T2979] ? lockdep_hardirqs_on+0x95/0x140
[ 18.783257][ T2979] ? syscall_enter_from_user_mode+0x2e/0x1c0
[ 18.789379][ T2979] do_syscall_64+0x44/0xa0
[ 18.794342][ T2979] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 18.800265][ T2979] RIP: 0033:0x7fef837538fe
[ 18.804785][ T2979] Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
[ 18.824787][ T2979] RSP: 002b:00007ffea8972ab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 18.834099][ T2979] RAX: ffffffffffffffda RBX: 000000007fff0000 RCX: 00007fef837538fe
[ 18.842179][ T2979] RDX: 0000000000000040 RSI: 000055f64a2af6d8 RDI: 0000000000000009
[ 18.850170][ T2979] RBP: 0000000000000040 R08: 000055f64a2af6b0 R09: 00007fef83823a60
[ 18.858243][ T2979] R10: 0000000000200000 R11: 0000000000000246 R12: 000055f64a2af6b0
[ 18.866500][ T2979] R13: 000055f64a2af6c8 R14: 000055f64a2b6720 R15: 000055f64a2b66d0
[ 18.874677][ T2979] </TASK>
[ 19.500327][ T2991] ================================================================================
[ 19.661875][ T2991] UBSAN: object-size-mismatch in net/unix/af_unix.c:1094:14
[ 19.717755][ T2991] member access within address ffff88801815e6c8 with insufficient space
[ 19.779625][ T2991] for an object of type 'struct sockaddr_un'
[ 19.844942][ T2991] CPU: 1 PID: 2991 Comm: udevadm Not tainted 5.16.0-rc3-syzkaller-01043-g1a2fb220edca-dirty #0
[ 19.855745][ T2991] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
[ 19.866130][ T2991] Call Trace:
[ 19.869498][ T2991] <TASK>
[ 19.872430][ T2991] dump_stack_lvl+0x1e3/0x2cb
[ 19.877100][ T2991] ? bfq_pos_tree_add_move+0x451/0x451
[ 19.882543][ T2991] ? panic+0x7e3/0x7e3
[ 19.886901][ T2991] ubsan_type_mismatch_common+0x1e6/0x390
[ 19.892637][ T2991] __ubsan_handle_type_mismatch_v1+0x4a/0x60
[ 19.898625][ T2991] unix_autobind+0x13e/0x4d0
[ 19.903239][ T2991] unix_stream_connect+0x622/0xbf0
[ 19.908342][ T2991] ? bpf_lsm_socket_connect+0x5/0x10
[ 19.914131][ T2991] ? security_socket_connect+0x9d/0xb0
[ 19.919703][ T2991] __x64_sys_connect+0x15b/0x1e0
[ 19.924797][ T2991] ? __sys_connect+0x170/0x170
[ 19.929592][ T2991] ? syscall_enter_from_user_mode+0x2e/0x1c0
[ 19.935598][ T2991] ? lockdep_hardirqs_on+0x95/0x140
[ 19.941067][ T2991] ? syscall_enter_from_user_mode+0x2e/0x1c0
[ 19.947035][ T2991] do_syscall_64+0x44/0xa0
[ 19.951623][ T2991] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 19.957618][ T2991] RIP: 0033:0x7f474d116d23
[ 19.962241][ T2991] Code: 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 2a 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 c3 0f 1f 40 00 48 83 ec 18 89 54 24 0c 48
[ 19.982635][ T2991] RSP: 002b:00007fffd159a368 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
[ 19.991348][ T2991] RAX: ffffffffffffffda RBX: 0000559aa0cda930 RCX: 00007f474d116d23
[ 19.999354][ T2991] RDX: 0000000000000013 RSI: 0000559aa0cda948 RDI: 0000000000000003
[ 20.007628][ T2991] RBP: 000000000000001e R08: 000000000000001e R09: 0030312e322e332d
[ 20.015622][ T2991] R10: 00007fffd159a4b4 R11: 0000000000000246 R12: 00007fffd159a380
[ 20.023593][ T2991] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000007
[ 20.031578][ T2991] </TASK>
[ 20.613100][ T2979] ================================================================================
[ 20.681439][ T2979] Kernel panic - not syncing: panic_on_warn set ...
[ 20.688430][ T2979] CPU: 0 PID: 2979 Comm: udevd Not tainted 5.16.0-rc3-syzkaller-01043-g1a2fb220edca-dirty #0
[ 20.698597][ T2979] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
[ 20.708677][ T2979] Call Trace:
[ 20.711976][ T2979] <TASK>
[ 20.714926][ T2979] dump_stack_lvl+0x1e3/0x2cb
[ 20.719636][ T2979] ? bfq_pos_tree_add_move+0x451/0x451
[ 20.725127][ T2979] ? panic+0x7e3/0x7e3
[ 20.729236][ T2979] panic+0x2f1/0x7e3
[ 20.733377][ T2979] ? ubsan_type_mismatch_common+0x2a4/0x390
[ 20.739478][ T2979] ? fb_is_primary_device+0xcc/0xcc
[ 20.744706][ T2979] ? panic+0x7e3/0x7e3
[ 20.748985][ T2979] ? mpage_readahead+0x6a0/0x6a0
[ 20.754056][ T2979] ubsan_type_mismatch_common+0x38c/0x390
[ 20.760262][ T2979] __ubsan_handle_type_mismatch_v1+0x4a/0x60
[ 20.766546][ T2979] mpage_readahead+0x588/0x6a0
[ 20.771338][ T2979] ? dio_await_one+0x250/0x250
[ 20.776581][ T2979] ? blkdev_fallocate+0x330/0x330
[ 20.781833][ T2979] ? put_page+0x90/0x90
[ 20.786019][ T2979] ? __alloc_pages+0x2fd/0x5f0
[ 20.790815][ T2979] ? blk_start_plug_nr_ios+0xaa/0x210
[ 20.796385][ T2979] read_pages+0x162/0x520
[ 20.800836][ T2979] ? page_cache_ra_unbounded+0x840/0x840
[ 20.806593][ T2979] ? filemap_add_folio+0x1ab/0x220
[ 20.811913][ T2979] ? add_to_page_cache_locked+0x90/0x90
[ 20.817565][ T2979] ? folio_alloc+0x47/0x50
[ 20.822089][ T2979] ? filemap_alloc_folio+0x1a9/0x1c0
[ 20.827414][ T2979] page_cache_ra_unbounded+0x6c1/0x840
[ 20.833601][ T2979] ? read_cache_pages_invalidate_pages+0xa0/0xa0
[ 20.840089][ T2979] ? do_page_cache_ra+0xde/0x100
[ 20.845127][ T2979] force_page_cache_ra+0x288/0x2e0
[ 20.850354][ T2979] filemap_read+0x809/0x23d0
[ 20.855676][ T2979] ? find_get_pages_range_tag+0x570/0x570
[ 20.861591][ T2979] ? memset+0x1f/0x40
[ 20.865601][ T2979] ? generic_file_read_iter+0x9e/0x4a0
[ 20.871203][ T2979] ? memset+0x1f/0x40
[ 20.875298][ T2979] ? init_sync_kiocb+0x303/0x4b0
[ 20.880251][ T2979] vfs_read+0x5cd/0x760
[ 20.884603][ T2979] ? kernel_read+0x1f0/0x1f0
[ 20.889200][ T2979] ? __fget_light+0xcc/0x170
[ 20.893838][ T2979] ksys_read+0x19f/0x2d0
[ 20.898157][ T2979] ? vfs_write+0x720/0x720
[ 20.902646][ T2979] ? syscall_enter_from_user_mode+0x2e/0x1c0
[ 20.908616][ T2979] ? lockdep_hardirqs_on+0x95/0x140
[ 20.913812][ T2979] ? syscall_enter_from_user_mode+0x2e/0x1c0
[ 20.919831][ T2979] do_syscall_64+0x44/0xa0
[ 20.924431][ T2979] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 20.930418][ T2979] RIP: 0033:0x7fef837538fe
[ 20.934855][ T2979] Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
[ 20.954802][ T2979] RSP: 002b:00007ffea8972ab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 20.963380][ T2979] RAX: ffffffffffffffda RBX: 000000007fff0000 RCX: 00007fef837538fe
[ 20.971639][ T2979] RDX: 0000000000000040 RSI: 000055f64a2af6d8 RDI: 0000000000000009
[ 20.979995][ T2979] RBP: 0000000000000040 R08: 000055f64a2af6b0 R09: 00007fef83823a60
[ 20.988207][ T2979] R10: 0000000000200000 R11: 0000000000000246 R12: 000055f64a2af6b0
[ 20.996338][ T2979] R13: 000055f64a2af6c8 R14: 000055f64a2b6720 R15: 000055f64a2b66d0
[ 21.004453][ T2979] </TASK>
[ 21.007945][ T2979] Kernel Offset: disabled
[ 21.012860][ T2979] Rebooting in 86400 seconds..

syzkaller build log:
go env (err=<nil>)
GO111MODULE="auto"
GOARCH="amd64"
GOBIN=""
GOCACHE="/syzkaller/.cache/go-build"
GOENV="/syzkaller/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/syzkaller/jobs/linux/gopath/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/syzkaller/jobs/linux/gopath"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.17"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build7159890=/tmp/go-build -gno-record-gcc-switches"

git status (err=<nil>)
HEAD detached at 8bcc32a67
nothing to commit, working tree clean

go list -f '{{.Stale}}' ./sys/syz-sysgen | grep -q false || go install ./sys/syz-sysgen
make .descriptions
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=8bcc32a67bc7180173447e1a78c03dae096b4231 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20220415-122244'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-fuzzer github.com/google/syzkaller/syz-fuzzer
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=8bcc32a67bc7180173447e1a78c03dae096b4231 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20220415-122244'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=8bcc32a67bc7180173447e1a78c03dae096b4231 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20220415-122244'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-stress github.com/google/syzkaller/tools/syz-stress
mkdir -p ./bin/linux_amd64
gcc -o ./bin/linux_amd64/syz-executor executor/executor.cc \
-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -static-pie -fpermissive -w -DGOOS_linux=1 -DGOARCH_amd64=1 \
-DHOSTGOOS_linux=1 -DGIT_REVISION=\"8bcc32a67bc7180173447e1a78c03dae096b4231\"

Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=13defd8a880000

Tested on:

commit: 1a2fb220 skbuff: Extract list pointers to silence comp..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel config: https://syzkaller.appspot.com/x/.config?x=7f37c0162d15e714
dashboard link: https://syzkaller.appspot.com/bug?extid=ef17b5b364116518fd65
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=146ed6ba880000