Re: kern/60568: panic locking against myself (p->p_lock) in NFS from sysctl_vmproc

["Greg A. Woods via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR kern/60568; it has been noted by GNATS.

From: "Greg A. Woods" <woods%planix.ca@localhost>
To: NetBSD GNATS <gnats-bugs%NetBSD.org@localhost>
Cc: 
Subject: Re: kern/60568: panic locking against myself (p->p_lock) in NFS from sysctl_vmproc 
Date: Thu, 24 Sep 2026 10:19:53 -0700

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 Indeed the pullup to the release branches would be appreciated!
 
 Looks like the lock caused it to fail to reboot too?  It was hung after
 the dump finished and I sent it a BREAK via conserver.  After the
 "reboot" the bootstrap ran (I saw the MBR boot message on the VGA
 screen) but it didn't seem to respond on the serial port and I had to
 power cycle it to get it to full reboot.  It's a ancient Dell PE2650.
 
 This is from a stock build of netbsd-10 from yesterday:
 
 $ uname -a
 NetBSD once 10.2_STABLE NetBSD 10.2_STABLE (GENERIC) #88: Wed Sep 23 01:21:04 PDT 2026  sysbuild@once:/home/sysbuild/i386/obj/home/sysbuild/src/sys/arch/i386/compile/GENERIC i386
 
 
 [ 12701.1919017] Mutex error: mutex_vector_enter,548: locking against myself
 
 [ 12701.2019207] lock address : c8ca35c0
 [ 12701.2019207] current cpu  :                  1
 [ 12701.2119255] current lwp  : 0x00000000c8c87680
 [ 12701.2119255] owner field  : 0x00000000c8c87680 wait/spin:                0/0
 
 [ 12701.2219370] panic: lock error: Mutex: mutex_vector_enter,548: locking against myself: lock 0xc8ca35c0 cpu 1 lwp 0xc8c87680
 [ 12701.2319452] cpu1: Begin traceback...
 [ 12701.2419550] vpanic(c12a9f60,e7cf7904,e7cf79b4,c0cd12bd,c12a9f60,c12a6680,c11a12bc,224,c12a664f,c8ca35c0) at netbsd:vpanic+0x196
 [ 12701.2519695] panic(c12a9f60,c12a6680,c11a12bc,224,c12a664f,c8ca35c0,1,c8c87680,c11a12bc,61633863) at netbsd:panic+0x18
 [ 12701.2719967] lockdebug_abort(c11a12bc,224,c8ca35c0,c14f2dc4,c12a664f,c8c87680,c8c87680,e7cf7a40,c0c96822,c12a664f) at netbsd:lockdebug_abort+0x11f
 [ 12701.2920236] mutex_abort(c12a664f,0,c0d0d0d1,0,c683b500,0,0,c8c87680,0,0) at netbsd:mutex_abort+0x2f
 [ 12701.3020374] mutex_vector_enter(c8ca35c0,c8dab2c0,0,c6610e00,e7cf7a90,c0bd2048,c8c87680,e7cf7a74,0,1000000) at netbsd:mutex_vector_enter+0x33b
 [ 12701.3220626] sigpending1(c8c87680,e7cf7a74,0,1000000,c6610e04,0,0,c8c87680,c683b500,0) at netbsd:sigpending1+0x20
 [ 12701.3320757] nfs_rcvlock(c6610e00,c8dab2c0,c683b500,c8dab2c0,c8c87680,0,e7cf7b4c,0,c6787700,24) at netbsd:nfs_rcvlock+0xbb
 [ 12701.3420892] nfs_request(c8d2ed44,c6787700,4,c8c87680,c8a77940,e7cf7bf4,e7cf7bf8,e7cf7bec,0,c6787800) at netbsd:nfs_request+0x386
 [ 12701.3621155] nfs_access(e7cf7c24,0,140,c11a4630,c8d3dc80,140,c8a77940,c8d3dc80,e7cf7d54,c0d1d803) at netbsd:nfs_access+0x1e0
 [ 12701.3721281] VOP_ACCESS(c8d3dc80,140,c8a77940,c644f068,0,40,0,c0c969a9,c5ddf0ba,50) at netbsd:VOP_ACCESS+0x63
 [ 12701.3921548] getcwd_common(c8e88040,c63e93c0,e7cf7d80,c644f068,ff,1,c8c87680,c644f268,c8d65300,c644f25a) at netbsd:getcwd_common+0x263
 [ 12701.4021682] vnode_to_path(c644f068,200,c8ce8900,c8c87680,c8d65300,0,c8a31dfc,c644f000,c8a31df8,2dea) at netbsd:vnode_to_path+0xb5
 [ 12701.4221937] sysctl_vmproc(e7cf7f04,3,bb0bd000,e7cf7ef8,0,0,e7cf7efc,c8c87680,c5e06304,f000) at netbsd:sysctl_vmproc+0x626
 [ 12701.4422203] sysctl_dispatch(e7cf7efc,5,bb0bd000,e7cf7ef8,0,0,e7cf7efc,c8c87680,c5e06304,e520) at netbsd:sysctl_dispatch+0x99
 [ 12701.4522338] sys___sysctl(c8c87680,e7cf7f68,e7cf7f60,c8ade600,1,ca,e7cf7f60,e7cf7f68,0,0) at netbsd:sys___sysctl+0xda
 [ 12701.4722598] syscall() at netbsd:syscall+0x1d6
 [ 12701.4822741] --- syscall (number 202) ---
 [ 12701.4822741] bb460b87:
 [ 12701.4822741] cpu1: End traceback...
 
 [ 12701.4922887] dumping to dev 19,1 offset 525311
 [ 12701.4922887] dump 171 170 169 168 167 166 165 164 163 162 161 160 159 158 157 156 155 154 153 152 151 150 149 148 147 146 145 144 143 142 141 140 139 138 137 136 135 134 133 132 131 130 129 128 127 126 125 124 123 122 121 120 119 118 117 116 115 114 113 112 111 110 109 108 107 106 105 104 103 102 101 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 succeeded
 
 [halt sent]
 [ 68530.7779193] fatal breakpoint trap in supervisor mode
 [ 68530.7779193] trap type 1 code 0 eip 0xc0127f74 cs 0x8 eflags 0x202 cr2 0xaf3af000 ilevel 0x8 esp 0xdd5e1e8c
 [ 68530.7779193] curlwp 0xc90ff780 pid 12616 lid 12616 lowest kstack 0xe7ef62c0
 Stopped in pid 12616.12616 (sh) at      netbsd:breakpoint+0x4:  popl    %ebp
 db{0}> bt
 breakpoint(c612926c,5,0,6ab551c7,0,c6129344,c61293cc,c61e0002,c61e1000,dd5e1ec6)
  at netbsd:breakpoint+0x4
 comintr(c6129200,c0cbab27,1ec,686e98,c150da98,6,1,0,c61e1000,c0105a48) at netbsd
 :comintr+0x8c2
 intr_kdtrace_wrapper(c62161c0,dd5e1ec4,6,c6210010,30,c62c0010,c6210010,6,1,dd5e1
 f44) at netbsd:intr_kdtrace_wrapper+0x2d
 Xintr_ioapic_edge7() at netbsd:Xintr_ioapic_edge7+0xc8
 --- interrupt ---
 _kernel_lock(1,0,dd5e1f70,c049ebfb,c14bc0c0,0,0,0,c61c1000,c010b5ec) at netbsd:_
 kernel_lock+0xca
 intr_biglock_wrapper(c5e18900,e7ef7f64,0,0,0,0,0,0,0,0) at netbsd:intr_biglock_w
 rapper+0x17
 --- switch to interrupt stack ---
 Xintr_ioapic_level1() at netbsd:Xintr_ioapic_level1+0xcc
 --- interrupt ---
 netbsd:Xtrap0e+0x4c:
 db{0}>
 
 --
 						Greg A. Woods
 						Planix, Inc.
 
 <woods%planix.ca@localhost>        +1 250 762-7675        http://www.planix.ca/
 
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