[syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 46ae4d0a4897 Merge git://git.kernel.org/pub/scm/linux/kern..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=106a549f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=3e10d80c64e440c0
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
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=144e27c7980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c16ef5753326/disk-46ae4d0a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4a3a038d0ccf/vmlinux-46ae4d0a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/244ada956332/bzImage-46ae4d0a.xz

The issue was bisected to:

commit 5a781ccbd19e4664babcbe4b4ead7aa2b9283d22
Author: Vinicius Costa Gomes <viniciu...@intel.com>
Date: Sat Sep 29 00:59:43 2018 +0000

tc: Add support for configuring the taprio scheduler

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10311900580000
final oops: https://syzkaller.appspot.com/x/report.txt?x=12311900580000
console output: https://syzkaller.appspot.com/x/log.txt?x=14311900580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8bb3e2...@syzkaller.appspotmail.com
Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler")

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-...D } 2685 jiffies s: 3289 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5444 Comm: syz-executor Not tainted 6.11.0-rc7-syzkaller-01396-g46ae4d0a4897 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:taprio_set_budgets+0x116/0x370 net/sched/sch_taprio.c:666
Code: 44 24 10 4c 89 74 24 18 4d 89 f5 45 31 ff 48 89 5c 24 08 bf 10 00 00 00 4c 89 fe e8 74 8f d2 f7 49 83 ff 0f 0f 87 63 01 00 00 <4c> 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74
RSP: 0018:ffffc90000007c30 EFLAGS: 00000093
RAX: 0000000000010000 RBX: ffff888028fdb130 RCX: ffff888030aada00
RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000010
RBP: 0000000000000000 R08: ffffffff89c1021c R09: 1ffff110051cea10
R10: dffffc0000000000 R11: ffffed10051cea11 R12: 0000000000000004
R13: ffff888028e75008 R14: ffff888028e75000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b8800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb58963cff8 CR3: 00000000311f6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
advance_sched+0x98d/0xca0 net/sched/sch_taprio.c:977
__run_hrtimer kernel/time/hrtimer.c:1689 [inline]
__hrtimer_run_queues+0x59b/0xd50 kernel/time/hrtimer.c:1753
hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1815
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline]
__sysvec_apic_timer_interrupt+0x110/0x3f0 arch/x86/kernel/apic/apic.c:1049
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x9/0x2a00 arch/x86/kernel/unwind_orc.c:469
Code: 4c 89 f7 e8 69 ad b9 00 e9 53 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 <41> 55 41 54 53 48 81 ec a0 00 00 00 48 89 fd 49 bd 00 00 00 00 00
RSP: 0018:ffffc9000422f120 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff820edaf2 RCX: ffff888030aada00
RDX: dffffc0000000000 RSI: ffffffff820edaf2 RDI: ffffc9000422f140
RBP: ffffc9000422f1d0 R08: 000000000000000a R09: ffffc9000422f230
R10: 0000000000000003 R11: ffffffff817f2f80 R12: ffff888030aada00
R13: ffffffff817f2f80 R14: ffffc9000422f220 R15: ffffc9000422f140
arch_stack_walk+0x151/0x1b0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
__call_rcu_common kernel/rcu/tree.c:3106 [inline]
call_rcu+0x167/0xa70 kernel/rcu/tree.c:3210
remove_vma mm/mmap.c:189 [inline]
remove_mt mm/mmap.c:2415 [inline]
do_vmi_align_munmap+0x155c/0x18c0 mm/mmap.c:2758
do_vmi_munmap+0x261/0x2f0 mm/mmap.c:2830
__vm_munmap+0x1fc/0x400 mm/mmap.c:3109
elf_map fs/binfmt_elf.c:383 [inline]
elf_load+0x2d8/0x6f0 fs/binfmt_elf.c:408
load_elf_binary+0xeba/0x2680 fs/binfmt_elf.c:1141
search_binary_handler fs/exec.c:1827 [inline]
exec_binprm fs/exec.c:1869 [inline]
bprm_execve+0xaf8/0x1770 fs/exec.c:1920
do_execveat_common+0x55f/0x6f0 fs/exec.c:2027
do_execve fs/exec.c:2101 [inline]
__do_sys_execve fs/exec.c:2177 [inline]
__se_sys_execve fs/exec.c:2172 [inline]
__x64_sys_execve+0x92/0xb0 fs/exec.c:2172
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb5887b0df7
Code: Unable to access opcode bytes at 0x7fb5887b0dcd.
RSP: 002b:00007fb58963ce78 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007fb588815ef0 RCX: 00007fb5887b0df7
RDX: 00007ffedbc5b9b0 RSI: 00007ffedbc5bbf0 RDI: 00007ffedbc5cef5
RBP: 00007ffedbc5ba20 R08: 00007fb58963cf20 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 000055558020fa80
R13: 0000000000000100 R14: 00007ffedbc5b9d0 R15: 00007ffedbc5b780
</TASK>


---
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#syz undup

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: a74c7a58ca2c net: freescale: ucc_geth: Return early when T..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=16fdf39a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=323fe5bdde2384a5
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13d8639a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154863fa580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/50a3e60a3908/disk-a74c7a58.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ee6a6a2a52e4/vmlinux-a74c7a58.xz
kernel image: https://storage.googleapis.com/syzbot-assets/033a07d12b3e/bzImage-a74c7a58.xz

The issue was bisected to:

commit 5a781ccbd19e4664babcbe4b4ead7aa2b9283d22
Author: Vinicius Costa Gomes <viniciu...@intel.com>
Date: Sat Sep 29 00:59:43 2018 +0000

tc: Add support for configuring the taprio scheduler

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10311900580000
final oops: https://syzkaller.appspot.com/x/report.txt?x=12311900580000
console output: https://syzkaller.appspot.com/x/log.txt?x=14311900580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8bb3e2...@syzkaller.appspotmail.com
Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler")

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=b674/1/0x4000000000000000 softirq=16193/16205 fqs=2
rcu: (detected by 0, t=10502 jiffies, g=13757, q=3905 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6128 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x3a/0xb0 kernel/rcu/tree.c:751
Code: e8 bb 0d b3 09 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 0d 9b 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 8c 1d 80 00 48 c7 c3 d8 56 81 92 49 03 1e 48 89
RSP: 0018:ffffc90000a08c70 EFLAGS: 00000046
RAX: 1ffffffff1b361bb RBX: 0000000000000001 RCX: 0000000000010002
RDX: 0000000000000000 RSI: ffffffff8bc086c0 RDI: ffffffff8bc08680
RBP: ffffffff81ae6da2 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: 0000000000000000
R13: ffff8880b8728258 R14: ffffffff8d9b0dd8 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888125f1e000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f9426807ff8 CR3: 0000000077a18000 CR4: 00000000003526f0
Call Trace:
<IRQ>
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x5f/0x340 kernel/locking/lockdep.c:5831
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:170
__run_hrtimer kernel/time/hrtimer.c:1781 [inline]
__hrtimer_run_queues+0x5e2/0xc30 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:deref_stack_reg+0x3/0x230 arch/x86/kernel/unwind_orc.c:418
Code: e8 12 f8 b2 00 48 8b 4c 24 18 e9 f2 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 41 55 41 54 53 48 83 ec 20 48 89 54 24 18 49 89 f0 49 89 ff
RSP: 0018:ffffc90002f16e00 EFLAGS: 00000283
RAX: fffffffffffffff0 RBX: ffffffff9025420e RCX: 0000000000000000
RDX: ffffc90002f16f28 RSI: ffffc90002f17ad0 RDI: ffffc90002f16ee8
RBP: dffffc0000000000 R08: ffffc90002f16f47 R09: 0000000000000000
R10: ffffc90002f16f38 R11: fffff520005e2de9 R12: ffffc90002f16f38
R13: 1ffff920005e2ddf R14: ffffc90002f16ee8 R15: 1ffffffff204a842
unwind_next_frame+0x18cc/0x23d0 arch/x86/kernel/unwind_orc.c:-1
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270
mt_alloc_one lib/maple_tree.c:174 [inline]
mas_alloc_nodes+0x291/0x350 lib/maple_tree.c:1110
mas_preallocate+0x2e0/0x670 lib/maple_tree.c:5194
vma_iter_prealloc mm/vma.h:502 [inline]
vma_shrink+0x18d/0x510 mm/vma.c:1200
relocate_vma_down+0x4d4/0x4f0 mm/vma_exec.c:91
setup_arg_pages+0x5cf/0xa90 fs/exec.c:690
load_elf_binary+0xba4/0x2740 fs/binfmt_elf.c:1028
search_binary_handler fs/exec.c:1669 [inline]
exec_binprm fs/exec.c:1701 [inline]
bprm_execve+0x92e/0x1400 fs/exec.c:1753
do_execveat_common+0x510/0x6a0 fs/exec.c:1859
do_execve fs/exec.c:1933 [inline]
__do_sys_execve fs/exec.c:2009 [inline]
__se_sys_execve fs/exec.c:2004 [inline]
__x64_sys_execve+0x94/0xb0 fs/exec.c:2004
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f94259c2e17
Code: Unable to access opcode bytes at 0x7f94259c2ded.
RSP: 002b:00007f9426807df8 EFLAGS: 00000206 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007ffd48e33ef5 RCX: 00007f94259c2e17
RDX: 00007ffd48e32ba0 RSI: 00007ffd48e32de0 RDI: 00007ffd48e33ef5
RBP: 00007f9426807e70 R08: 00007f9426807f20 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000206 R12: 00007ffd48e32de0
R13: 00007ffd48e32ba0 R14: 0000000000000000 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 10495 jiffies! g13757 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27480 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5203 Comm: udevd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xcc5/0x1260 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 d4 97 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f 93 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 63 93
RSP: 0000:ffffc90003057820 EFLAGS: 00000293
RAX: ffffffff81b5654d RBX: 1ffff110170e8129 RCX: ffff88807d153d00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003057950 R08: ffffffff8f822e77 R09: 1ffffffff1f045ce
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: ffff8880b8740948
R13: dffffc0000000000 R14: ffff8880b863bb00 R15: 0000000000000001
FS: 00007f6e0f393880(0000) GS:ffff888125e1e000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000055ec54628550 CR3: 000000007d7b8000 CR4: 00000000003526f0
Call Trace:
<TASK>
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472
flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103
wp_page_copy mm/memory.c:3785 [inline]
do_wp_page+0x1bb1/0x5810 mm/memory.c:4180
handle_pte_fault mm/memory.c:6289 [inline]
__handle_mm_fault mm/memory.c:6411 [inline]
handle_mm_fault+0x14c5/0x32b0 mm/memory.c:6580
do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f6e0ecb5dfe
Code: 00 00 66 0f ef c0 41 0f 11 44 24 20 49 89 54 24 10 49 89 74 24 18 4c 89 66 10 4c 89 62 18 48 89 c2 48 83 ca 01 49 89 54 24 08 <49> 89 04 04 48 83 c4 10 5b 41 5c 41 5d c3 0f 1f 40 00 48 89 cf 48
RSP: 002b:00007fff1a84f050 EFLAGS: 00010206
RAX: 0000000000002a20 RBX: 0000000000000740 RCX: 000055ec54627e10
RDX: 0000000000002a21 RSI: 00007f6e0edf1b20 RDI: 000055ec54627e10
RBP: 00007f6e0edf1ac0 R08: 0000000000000740 R09: 0000000000000010
R10: 000055ec24e255e0 R11: 0000000000000004 R12: 000055ec54625b30
R13: 00007f6e0edf1ac0 R14: 0000000000000740 R15: 00007f6e0edf1ac0
</TASK>


---