Message-ID: <e2498b0f-cc3d-43da-8422-9ef237d16d43@linux.ibm.com>
Date: Wed, 12 Mar 2025 11:32:54 +0530
From: Venkat Rao Bagalkote <venkat88@...ux.ibm.com>
To: Hari Bathini <hbathini@...ux.ibm.com>, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org,
        Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: Re: PowerPC: Observing Kernel softlockup while running ftrace
 selftest


On 10/03/25 4:25 pm, Hari Bathini wrote:
> Venkat, can you confirm if the issue is reproducible
> disabling CONFIG_PPC_IRQ_SOFT_MASK_DEBUG  ?

Hari,

This issue is reproducible after diabling CONFIG_PPC_IRQ_SOFT_MASK_DEBUG.

# powerpc Debugging
#
CONFIG_PPC_DISABLE_WERROR=y
CONFIG_PRINT_STACK_DEPTH=64
# CONFIG_HCALL_STATS is not set
CONFIG_PPC_EMULATED_STATS=y
# CONFIG_CODE_PATCHING_SELFTEST is not set
CONFIG_JUMP_LABEL_FEATURE_CHECKS=y
# CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG is not set
CONFIG_FTR_FIXUP_SELFTEST=y
CONFIG_MSI_BITMAP_SELFTEST=y
# CONFIG_GUEST_STATE_BUFFER_TEST is not set
# CONFIG_PPC_IRQ_SOFT_MASK_DEBUG is not set
CONFIG_PPC_RFI_SRR_DEBUG=y
CONFIG_XMON=y
# CONFIG_XMON_DEFAULT is not set
CONFIG_XMON_DISASSEMBLY=y
CONFIG_XMON_DEFAULT_RO_MODE=y
CONFIG_DEBUGGER=y
CONFIG_BOOTX_TEXT=y
# CONFIG_PPC_EARLY_DEBUG is not set
# end of powerpc Debugging

Regards,

Venkat.

>
>
> On 06/03/25 6:04 pm, Venkat Rao Bagalkote wrote:
>> Greetings!!!
>>
>>
>> I am observing soft lock up's while running ftrace selftest on linux- 
>> next kernel.
>>
>> Kernel Version: next-20250305
>>
>> make run_tests
>> TAP version 13
>> 1..2
>> # timeout set to 0
>> # selftests: ftrace: poll
>> # Error: Polling file is not specified
>> not ok 1 selftests: ftrace: poll # exit=255
>> # timeout set to 0
>> # selftests: ftrace: ftracetest-ktap
>> # TAP version 13
>> # 1..155
>> # ok 1 Basic trace file check
>> # ok 2 Basic test for tracers
>> # ok 3 Basic trace clock test
>> # ok 4 Basic event tracing check
>> # ok 5 Test tracefs GID mount option
>> # ok 6 Change the ringbuffer size
>> # ok 7 Change the ringbuffer sub-buffer size
>> # ok 8 Snapshot and tracing_cpumask
>> # ok 9 Snapshot and tracing setting
>> # ok 10 Test file and directory ownership changes for eventfs
>> # ok 11 Basic tests on writing to trace_marker
>> # ok 12 trace_pipe and trace_marker
>> # not ok 13 Test ftrace direct functions against tracers # UNRESOLVED
>> # not ok 14 Test ftrace direct functions against kprobes # UNRESOLVED
>> # ok 15 Generic dynamic event - add/remove probes with BTF arguments 
>> # SKIP
>> # ok 16 Generic dynamic event - add/remove eprobe events
>> # ok 17 Generic dynamic event - Repeating add/remove fprobe events # 
>> SKIP
>> # ok 18 Generic dynamic event - add/remove fprobe events # SKIP
>> # ok 19 Generic dynamic event - add/remove kprobe events
>> # ok 20 Generic dynamic event - add/remove synthetic events
>> # ok 21 Generic dynamic event - add/remove tracepoint probe events on 
>> module # SKIP
>> # ok 22 Generic dynamic event - add/remove tracepoint probe events # 
>> SKIP
>> # ok 23 Generic dynamic event - add/remove/test uprobe events
>> # ok 24 Generic dynamic event - selective clear (compatibility)
>> # ok 25 Checking dynamic events limitations
>> # ok 26 Event probe event parser error log check
>> # ok 27 Fprobe event VFS type argument # SKIP
>> # ok 28 Function return probe entry argument access # SKIP
>> # ok 29 Fprobe event parser error log check # SKIP
>> # ok 30 Generic dynamic event - generic clear event
>> # ok 31 Generic dynamic event - check if duplicate events are caught
>> # ok 32 Tracepoint probe event parser error log check # SKIP
>> # ok 33 event tracing - enable/disable with event level files
>> # not ok 34 event tracing - enable/disable with module event # 
>> UNRESOLVED
>> # ok 35 event tracing - restricts events based on pid notrace filtering
>> # ok 36 event tracing - restricts events based on pid
>> # ok 37 event tracing - enable/disable with subsystem level files
>> # ok 38 event tracing - enable/disable with top level files
>> # not ok 39 Test trace_printk from module # UNRESOLVED
>> # ok 40 event filter function - test event filtering on functions
>> # ok 41 ftrace - function graph filters with stack tracer
>> # ok 42 ftrace - function graph filters
>> # ok 43 ftrace - function graph filters
>> # ok 44 ftrace - function profiler with function graph tracing
>> # ok 45 ftrace - function graph print function return value # SKIP
>> # ok 46 ftrace - function trace with cpumask
>> # ok 47 ftrace - test for function event triggers
>> # ok 48 ftrace - function glob filters
>> # ok 49 ftrace - function pid notrace filters
>> # ok 50 ftrace - function pid filters
>> # ok 51 ftrace - stacktrace filter command
>>
>>
>> Warnings:
>>
>>
>> [ 2668.008907] watchdog: BUG: soft lockup - CPU#0 stuck for 2265s! 
>> [swapper/0:0]
>> [ 2668.008954] Modules linked in: bonding(E) nft_fib_inet(E) 
>> nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) 
>> nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) 
>> nft_chain_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) 
>> nf_defrag_ipv4(E) ip_set(E) rfkill(E) nf_tables(E) nfnetlink(E) 
>> mlx5_ib(E) ib_uverbs(E) ib_core(E) pseries_rng(E) vmx_crypto(E) 
>> dax_pmem(E) drm(E) drm_panel_orientation_quirks(E) xfs(E) sr_mod(E) 
>> cdrom(E) sd_mod(E) sg(E) lpfc(E) nd_pmem(E) nvmet_fc(E) nd_btt(E) 
>> ibmvscsi(E) scsi_transport_srp(E) ibmveth(E) nvmet(E) nvme_fc(E) 
>> mlx5_core(E) nvme_fabrics(E) papr_scm(E) mlxfw(E) nvme_core(E) 
>> libnvdimm(E) tls(E) psample(E) scsi_transport_fc(E) fuse(E)
>> [ 2668.010198] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Kdump: loaded 
>> Tainted: G        W   EL     6.14.0-rc5-next-20250305 #1
>> [ 2668.010242] Tainted: [W]=WARN, [E]=UNSIGNED_MODULE, [L]=SOFTLOCKUP
>> [ 2668.010276] Hardware name: IBM,8375-42A POWER9 (architected) 
>> 0x4e0202 0xf000005 of:IBM,FW950.80 (VL950_131) hv:phyp pSeries
>> [ 2668.010316] NIP:  c000000000039f90 LR: c00000000007c1a4 CTR: 
>> c000000000039f44
>> [ 2668.010354] REGS: c000000002c9f538 TRAP: 0900   Tainted: G        
>> W EL      (6.14.0-rc5-next-20250305)
>> [ 2668.010392] MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 
>> 22002844  XER: 20040000
>> [ 2668.010639] CFAR: 0000000000000000 IRQMASK: 0
>> [ 2668.010639] GPR00: c00000000007c1a4 c000000002c9f510 
>> c000000001688100 c000000002c9f508
>> [ 2668.010639] GPR04: 8000000002823033 c000000002c61700 
>> c000000002c61700 0000000000000178
>> [ 2668.010639] GPR08: 0000000000000002 0000000000000049 
>> 0000000000000000 0000000000002000
>> [ 2668.010639] GPR12: c000000000328588 c000000003020000 
>> 0000000000000000 0000000000000000
>> [ 2668.010639] GPR16: 0000000000000000 0000000000000000 
>> 0000000000000000 0000000000000000
>> [ 2668.010639] GPR20: 0000000000000000 0000000000000000 
>> 0000000000000000 0000000000000000
>> [ 2668.010639] GPR24: 0000000000000000 0000000000000000 
>> 0000000000000000 0000000000000003
>> [ 2668.010639] GPR28: 0000000000000002 0000000000000000 
>> fcffffffffffffff c000000002c9f760
>> [ 2668.011572] NIP [c000000000039f90] 
>> __replay_soft_interrupts+0x5c/0x22c
>> [ 2668.011628] LR [c00000000007c1a4] return_to_handler+0x0/0x40
>> [ 2668.011680] Call Trace:
>> [ 2668.011715] [c000000002c9f510] [c00000000003a018] 
>> __replay_soft_interrupts+0xe4/0x22c (unreliable)
>> [ 2668.011809] [c000000002c9f6c0] [c00000000007c1a4] 
>> return_to_handler+0x0/0x40 (replay_soft_interrupts+0x28/0x40)
>> [ 2668.011918] [c000000002c9f6e0] [c00000000007c1a4] 
>> return_to_handler+0x0/0x40 (interrupt_exit_kernel_prepare+0x20c/0x250)
>> [ 2668.012025] [c000000002c9f730] [c00000000000da68] 
>> interrupt_return_srr_kernel+0x8/0x18c
>> [ 2668.012098] --- interrupt: 700 at arch_local_irq_restore+0x90/0x280
>> [ 2668.012149] NIP:  c00000000003a1f0 LR: c00000000033b458 CTR: 
>> 00000000000008fb
>> [ 2668.012188] REGS: c000000002c9f760 TRAP: 0700   Tainted: G        
>> W EL      (6.14.0-rc5-next-20250305)
>> [ 2668.012224] MSR:  8000000002823033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE> 
>> CR: 28002844  XER: 20040000
>> [ 2668.012509] CFAR: c00000000033b454 IRQMASK: 0
>> [ 2668.012509] GPR00: c00000000033b458 c000000002c9fa00 
>> c000000001688100 0000000000000000
>> [ 2668.012509] GPR04: 000000000000001c 0000000000000000 
>> 0000000000000018 c0000000c89ff980
>> [ 2668.012509] GPR08: c0000000c89ff980 0000000000000000 
>> c0000000c89ff980 0000000028002844
>> [ 2668.012509] GPR12: c000000000325fd0 c000000003020000 
>> c0000000000ffde8 0000000000000000
>> [ 2668.012509] GPR16: 0000000000000000 0000000000000000 
>> 0000000000000000 0000000000000000
>> [ 2668.012509] GPR20: 0000000000c00000 0000000000000008 
>> 0000000000000000 0000000000000000
>> [ 2668.012509] GPR24: 0000000000000000 c000000000000000 
>> fffffffffffffeff c000000004070500
>> [ 2668.012509] GPR28: 0000000000000002 0000000000000003 
>> 00000000913f411d fcffffffffffffff
>> [ 2668.013441] NIP [c00000000003a1f0] arch_local_irq_restore+0x90/0x280
>> [ 2668.013492] LR [c00000000033b458] rb_commit+0xc8/0x280
>> [ 2668.013541] --- interrupt: 700
>> [ 2668.013575] [c000000002c9fa00] [0000000000000000] 0x0 (unreliable)
>> [ 2668.013667] [c000000002c9fa40] [c00000000033b458] 
>> rb_commit+0xc8/0x280
>> [ 2668.013738] [c000000002c9fa70] [c00000000033e6a4] 
>> ring_buffer_unlock_commit+0x38/0x1b0
>> [ 2668.013807] [c000000002c9fab0] [c00000000034d53c] 
>> trace_function+0xcc/0x19c
>> [ 2668.013877] [c000000002c9fb00] [c00000000035ec14] 
>> function_trace_call+0x154/0x1d4
>> [ 2668.013951] [c000000002c9fb50] [c000000000329f88] 
>> arch_ftrace_ops_list_func+0x15c/0x290
>> [ 2668.014021] [c000000002c9fc20] [c00000000007c0cc] 
>> ftrace_call+0x4/0x4c
>> [ 2668.014092] [c000000002c9fdd0] [c0000000000ffde8] 
>> pseries_lpar_idle.part.0+0x10/0x164
>> [ 2668.014163] [c000000002c9fdf0] [c00000000007c1a4] 
>> return_to_handler+0x0/0x40 (arch_cpu_idle+0x50/0x120)
>> [ 2668.014269] [c000000002c9fe10] [c00000000007c1a4] 
>> return_to_handler+0x0/0x40 (default_idle_call+0x50/0x10c)
>> [ 2668.014375] [c000000002c9fe30] [c0000000001f52bc] 
>> cpuidle_idle_call+0x1b8/0x240
>> [ 2668.014447] [c000000002c9fe90] [c00000000007c1a4] 
>> return_to_handler+0x0/0x40 (do_idle+0x100/0x1ac)
>> [ 2668.014554] [c000000002c9fee0] [c00000000007c1a4] 
>> return_to_handler+0x0/0x40 (cpu_startup_entry+0x4c/0x50)
>> [ 2668.014661] [c000000002c9ff10] [c000000000011280] rest_init+0xf0/0xf4
>> [ 2668.014732] [c000000002c9ff40] [c000000002006604] 
>> start_kernel+0x50c/0x5e0
>> [ 2668.014806] [c000000002c9ffe0] [c00000000000ea9c] 
>> start_here_common+0x1c/0x20
>> [ 2668.014878] Code: 71298000 408201ec 892d0933 7d2a48f8 554a07fe 
>> 0b0a0000 792ad7e2 0b0a0000 61290040 38610028 992d0933 48042259 
>> <60000000> 39200000 e9410130 f9210160
>>
>>
>> If you fix this issue please add below tag.
>>
>> Reported-by: Venkat Rao Bagalkote <venkat88@...ux.ibm.com>
>>
>>
>> Regards,
>>
>> Venkat.
>>
>>
>

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