Re: [syzbot] [fuse?] INFO: task hung in fuse_chan_send

Re: [syzbot] [fuse?] INFO: task hung in fuse_chan_send

[syzbot]

Hello,

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

failed to apply patch:
error: corrupt patch at line 9



Tested on:

commit:         48a5a7ab Merge tag 'v7.2-rc4-smb3-client-fixes' of git..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c3d59be33cf7e9a
dashboard link: https://syzkaller.appspot.com/bug?extid=a531d1b1fb0fa2a75a73
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14167a32580000

Re: [syzbot] [fuse?] INFO: task hung in fuse_chan_send

[syzbot]

Hello,

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

failed to copy syz-execprog to VM: scp failed: failed to run ["scp" "-P" "1469" "-F" "/dev/null" "-o" "UserKnownHostsFile=/dev/null" "-o" "IdentitiesOnly=yes" "-o" "BatchMode=yes" "-o" "StrictHostKeyChecking=no" "-o" "ConnectTimeout=10" "-v" "-O" "/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/bin/linux_amd64/syz-execprog" "root@localhost:/syz-execprog"]: exit status 1



syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2963203302=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
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'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at fb92f11c47
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -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 -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"fb92f11c4789d9647a75c09c983dbee5c8488ccf\"
/usr/bin/ld: /tmp/ccvyw13H.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null



Tested on:

commit:         48a5a7ab Merge tag 'v7.2-rc4-smb3-client-fixes' of git..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c3d59be33cf7e9a
dashboard link: https://syzkaller.appspot.com/bug?extid=a531d1b1fb0fa2a75a73
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13cdc449580000

Re: [syzbot] [fuse?] INFO: task hung in fuse_chan_send

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in fuse_chan_send

INFO: task syz.0.17:5898 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:24904 pid:5898  tgid:5898  ppid:5825   task_flags:0x400040 flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7326
 request_wait_answer fs/fuse/dev.c:743 [inline]
 __fuse_request_send fs/fuse/dev.c:757 [inline]
 fuse_chan_send+0x1065/0x1ac0 fs/fuse/dev.c:833
 fuse_simple_request fs/fuse/fuse_i.h:1012 [inline]
 fuse_flush+0x66e/0x8b0 fs/fuse/file.c:504
 filp_flush+0xbd/0x190 fs/open.c:1471
 filp_close+0x1d/0x40 fs/open.c:1484
 __range_close fs/file.c:793 [inline]
 __do_sys_close_range fs/file.c:854 [inline]
 __se_sys_close_range+0x3d3/0x900 fs/file.c:818
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2b2b99ce59
RSP: 002b:00007ffdbb62c298 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007ffdbb62c380 RCX: 00007f2b2b99ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000028b59 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2ff20000 R11: 0000000000000246 R12: 00007ffdbb62c3c0
R13: 00007f2b2bc15fac R14: 0000000000028bf9 R15: 00007f2b2bc15fa0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/26:
 #0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u5:0/44:
 #0: ffff888042840140 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff888042840140 ((wq_completion)hci2){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc90000467c40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc90000467c40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffff888041e78ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1cb/0x3f0 net/bluetooth/hci_sync.c:331
4 locks held by kworker/u4:4/68:
 #0: ffff88803f2fd140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88803f2fd140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffff88801fc24440 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
 #2: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #2: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #2: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
 #2: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
 #3: ffff888044bed840 (&ifa->lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline]
 #3: ffff888044bed840 (&ifa->lock){+...}-{3:3}, at: addrconf_dad_stop+0xb7/0x420 net/ipv6/addrconf.c:2144
2 locks held by getty/5091:
 #0: ffff88803f6020a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900016002e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
3 locks held by kworker/0:7/5894:
 #0: ffff88801aca6940 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88801aca6940 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc90002fa7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc90002fa7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffff88804d9da250 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1fd/0x3b0 drivers/net/netdevsim/fib.c:1490
2 locks held by dhcpcd/6316:
 #0: ffff888041658800 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #0: ffff888041658800 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release net/socket.c:709 [inline]
 #0: ffff888041658800 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x82/0x220 net/socket.c:1501
 #1: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #1: ffffffff8e95ff28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 26 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


Tested on:

commit:         51cb1aa1 Merge tag 'loongarch-7.2' of git://git.kernel..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13910105580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c3d59be33cf7e9a
dashboard link: https://syzkaller.appspot.com/bug?extid=a531d1b1fb0fa2a75a73
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Note: no patches were applied.

Re: [syzbot] [fuse?] INFO: task hung in fuse_chan_send

[syzbot]

Hello,

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

failed to copy prog to VM: scp failed: failed to run ["scp" "-P" "25994" "-F" "/dev/null" "-o" "UserKnownHostsFile=/dev/null" "-o" "IdentitiesOnly=yes" "-o" "BatchMode=yes" "-o" "StrictHostKeyChecking=no" "-o" "ConnectTimeout=10" "-v" "-O" "/tmp/syzkaller1551263741" "root@localhost:/syzkaller1551263741"]: exit status 1



syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3447069114=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
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'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at fb92f11c47
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -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 -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"fb92f11c4789d9647a75c09c983dbee5c8488ccf\"
/usr/bin/ld: /tmp/ccUfkjN0.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null



Tested on:

commit:         48a5a7ab Merge tag 'v7.2-rc4-smb3-client-fixes' of git..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c3d59be33cf7e9a
dashboard link: https://syzkaller.appspot.com/bug?extid=a531d1b1fb0fa2a75a73
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1552e351580000

Re: [syzbot] [fuse?] INFO: task hung in fuse_chan_send

[syzbot]

Hello,

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

lost connection to test machine



syzkaller login: qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0xba000)
[  110.222965][ T1028] ata1.00: Read log 0x10 page 0x00 failed, Emask 0x1
[  110.225835][ T1028] ata1: failed to read log page 10h (errno=-5)
[  110.228573][ T1028] ata1.00: exception Emask 0x1 SAct 0xc000 SErr 0x0 action 0x0
[  110.243158][ T1028] ata1.00: irq_stat 0x40000000
[  110.247818][ T1028] ata1.00: failed command: WRITE FPDMA QUEUED
[  110.255077][ T1028] ata1.00: cmd 61/d0:70:36:41:04/05:00:00:00:00/40 tag 14 ncq dma 761856 out
[  110.255077][ T1028]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  110.273090][ T1028] ata1.00: status: { DRDY }
[  110.280653][ T1028] ata1.00: failed command: WRITE FPDMA QUEUED
[  110.291935][ T1028] ata1.00: cmd 61/e8:78:06:47:04/02:00:00:00:00/40 tag 15 ncq dma 380928 out
[  110.291935][ T1028]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  110.317045][ T1028] ata1.00: status: { DRDY }
[  110.325648][ T1028] ata1.00: configured for UDMA/100
[  110.332172][ T1028] ata1: EH complete
qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0x400000)
qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0x400000)
Warning: Permanently added '[localhost]:55333' (ED25519) to the list of known hosts.
2026/07/24 10:48:22 parsed 1 programs
2026/07/24 10:48:22 serving rpc on tcp://33671
[  120.451810][ T5301] cgroup: Unknown subsys name 'net'
[  120.509463][ T5301] cgroup: Unknown subsys name 'cpuset'
[  120.516681][ T5301] cgroup: Unknown subsys name 'rlimit'
[  137.844799][ T1332] ieee802154 phy0 wpan0: encryption failed: -22
[  137.847636][ T1332] ieee802154 phy1 wpan1: encryption failed: -22
[  178.182256][ T1028] ata1.00: NCQ disabled due to excessive errors
[  178.184972][ T1028] ata1.00: exception Emask 0x0 SAct 0x120 SErr 0x0 action 0x6 frozen
[  178.188645][ T1028] ata1.00: failed command: WRITE FPDMA QUEUED
[  178.191451][ T1028] ata1.00: cmd 61/00:28:36:01:05/20:00:00:00:00/40 tag 5 ncq dma 4194304 ou
[  178.191451][ T1028]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  178.199514][ T1028] ata1.00: status: { DRDY }
[  178.202584][ T1028] ata1.00: failed command: WRITE FPDMA QUEUED
[  178.205241][ T1028] ata1.00: cmd 61/00:40:36:61:05/20:00:00:00:00/40 tag 8 ncq dma 4194304 ou
[  178.205241][ T1028]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  178.213219][ T1028] ata1.00: status: { DRDY }
[  178.215375][ T1028] ata1: hard resetting link
[  178.533841][ T1028] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[  178.537972][ T1028] ata1.00: configured for UDMA/100
[  178.540726][ T1028] ata1: EH complete
qemu-system-x86_64: hw/ide/core.c:934: ide_dma_cb: Assertion `prep_size >= 0 && prep_size <= n * 512' failed.
Connection to localhost closed by remote host.


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build793079094=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
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'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at fb92f11c47
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=fb92f11c4789d9647a75c09c983dbee5c8488ccf -X github.com/google/syzkaller/prog.gitRevisionDate=20260626-134956"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -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 -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"fb92f11c4789d9647a75c09c983dbee5c8488ccf\"
/usr/bin/ld: /tmp/ccLzPndg.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null



Tested on:

commit:         48a5a7ab Merge tag 'v7.2-rc4-smb3-client-fixes' of git..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c3d59be33cf7e9a
dashboard link: https://syzkaller.appspot.com/bug?extid=a531d1b1fb0fa2a75a73
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=137f59c1580000

Re: [syzbot] [fuse?] INFO: task hung in fuse_chan_send

[syzbot]

Hello,

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

failed to apply patch:
error: corrupt patch at line 6



Tested on:

commit:         48a5a7ab Merge tag 'v7.2-rc4-smb3-client-fixes' of git..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c3d59be33cf7e9a
dashboard link: https://syzkaller.appspot.com/bug?extid=a531d1b1fb0fa2a75a73
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13373bde580000

Re: [syzbot] [fuse?] INFO: task hung in fuse_chan_send

[syzbot]

Hello,

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

failed to apply patch:
error: corrupt patch at line 6



Tested on:

commit:         48a5a7ab Merge tag 'v7.2-rc4-smb3-client-fixes' of git..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=3c3d59be33cf7e9a
dashboard link: https://syzkaller.appspot.com/bug?extid=a531d1b1fb0fa2a75a73
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14f396b9580000

[syzbot] [fuse?] INFO: task hung in fuse_chan_send

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    c425609d6ac4 Add linux-next specific files for 20260612
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1206c3b6580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d7a56b1e89b63439
dashboard link: https://syzkaller.appspot.com/bug?extid=a531d1b1fb0fa2a75a73
compiler:       Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=163c04ae580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7fab9a8df61a/disk-c425609d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c2577196651b/vmlinux-c425609d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/053557a7471e/bzImage-c425609d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a531d1b1fb0fa2a75a73@syzkaller.appspotmail.com

INFO: task syz.0.17:5995 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:27344 pid:5995  tgid:5994  ppid:5839   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x1709/0x5530 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 request_wait_answer fs/fuse/dev.c:743 [inline]
 __fuse_request_send fs/fuse/dev.c:757 [inline]
 fuse_chan_send+0x1068/0x1ad0 fs/fuse/dev.c:833
 fuse_simple_request fs/fuse/fuse_i.h:1012 [inline]
 fuse_do_getattr+0x370/0x690 fs/fuse/dir.c:1505
 fuse_update_get_attr+0x600/0x1300 fs/fuse/dir.c:1562
 vfs_getattr_nosec+0x2e1/0x430 fs/stat.c:213
 vfs_statx_path+0x2b/0x230 fs/stat.c:299
 vfs_statx+0x12e/0x200 fs/stat.c:356
 vfs_fstatat+0x11b/0x170 fs/stat.c:373
 __do_sys_newfstatat fs/stat.c:538 [inline]
 __se_sys_newfstatat fs/stat.c:532 [inline]
 __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0189d9ce59
RSP: 002b:00007f01893fe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007f018a015fa0 RCX: 00007f0189d9ce59
RDX: 0000000000000000 RSI: 0000200000000500 RDI: ffffffffffffff9c
RBP: 00007f0189e32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f018a016038 R14: 00007f018a015fa0 R15: 00007ffef89eaea8
 </TASK>

Showing all locks held in the system:
10 locks held by ktimers/0/16:
 #0: ffffffff8de611a0 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
 #1: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
 #2: ffff8880b8626260 (&base->expiry_lock){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #2: ffff8880b8626260 (&base->expiry_lock){+...}-{3:3}, at: timer_base_lock_expiry kernel/time/timer.c:1502 [inline]
 #2: ffff8880b8626260 (&base->expiry_lock){+...}-{3:3}, at: __run_timer_base+0x11a/0x9b0 kernel/time/timer.c:2384
 #3: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #3: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #3: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #3: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
 #4: ffffc90000157a80 ((&ndev->rs_timer)){+...}-{0:0}, at: expire_timers kernel/time/timer.c:1800 [inline]
 #4: ffffc90000157a80 ((&ndev->rs_timer)){+...}-{0:0}, at: __run_timers kernel/time/timer.c:2374 [inline]
 #4: ffffc90000157a80 ((&ndev->rs_timer)){+...}-{0:0}, at: __run_timer_base+0x683/0x9b0 kernel/time/timer.c:2386
 #5: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
 #6: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #6: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #6: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #6: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
 #7: ffffffff8de611a0 (local_bh){.+.+}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #7: ffffffff8de611a0 (local_bh){.+.+}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #7: ffffffff8de611a0 (local_bh){.+.+}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #7: ffffffff8de611a0 (local_bh){.+.+}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
 #8: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: debug_object_activate+0xa8/0x3a0 lib/debugobjects.c:873
 #9: ffff888037258af8 (&p->pi_lock){-...}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:572 [inline]
 #9: ffff888037258af8 (&p->pi_lock){-...}-{2:2}, at: try_to_wake_up+0x67/0x1430 kernel/sched/core.c:4292
1 lock held by khungtaskd/39:
 #0: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffffffff8dfcb040 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777
2 locks held by getty/5363:
 #0: ffff8880365650a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__find_rr_leaf+0x121/0x760 net/ipv6/route.c:840
Code: c0 33 c1 8d 48 c1 e8 03 48 89 44 24 70 4c 89 7c 24 38 4d 85 ff 74 4e 49 8d 9e 90 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 <84> c0 75 21 8b 1b 89 df 44 8b 64 24 4c 44 89 e6 e8 9a 71 e5 f7 44
RSP: 0018:ffffc90000157160 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff888036f70490 RCX: ffff88801d688000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
RBP: ffffc900001572b8 R08: 0000000000000000 R09: 0000000000000100
R10: ffffc90000157240 R11: fffff5200002ae4a R12: 1ffff1100783a48c
R13: dffffc0000000000 R14: ffff888036f70400 R15: ffffc900001573b8
FS:  0000000000000000(0000) GS:ffff888125ece000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559e696cf1f0 CR3: 000000002a2d2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 find_rr_leaf net/ipv6/route.c:892 [inline]
 rt6_select net/ipv6/route.c:936 [inline]
 fib6_table_lookup+0x3cb/0xb00 net/ipv6/route.c:2254
 ip6_pol_route+0x228/0x13e0 net/ipv6/route.c:2290
 pol_lookup_func include/net/ip6_fib.h:669 [inline]
 fib6_rule_lookup+0x563/0x740 net/ipv6/fib6_rules.c:123
 ip6_route_input_lookup net/ipv6/route.c:2359 [inline]
 ip6_route_input+0x78d/0xb20 net/ipv6/route.c:2662
 ip6_rcv_finish+0x141/0x280 net/ipv6/ip6_input.c:117
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6205 [inline]
 __netif_receive_skb net/core/dev.c:6318 [inline]
 process_backlog+0x3bf/0xc50 net/core/dev.c:6669
 __napi_poll+0xae/0x550 net/core/dev.c:7728
 napi_poll net/core/dev.c:7791 [inline]
 net_rx_action+0x621/0xd70 net/core/dev.c:7948
 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1155
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


---
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 syzkaller@googlegroups.com.

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)

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