Al Viro wrote:
> Try to check if this helps:
Yes, that helps. Thank you.
I used below version and the oops no longer occur.
---------- patch start ----------
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -532,10 +532,15 @@ static inline struct dentry *lock_parent(struct dentry *dentry)
struct dentry *parent = dentry->d_parent;
if (IS_ROOT(dentry))
return NULL;
+ if (WARN_ON_ONCE((int)dentry->d_lockref.count < 0)) {
+ pr_warn("dentry->d_lockref.count=%d dentry->d_sb->s_magic=%lx\n",
+ dentry->d_lockref.count, dentry->d_sb->s_magic);
+ return NULL;
+ }
if (likely(spin_trylock(&parent->d_lock)))
return parent;
- spin_unlock(&dentry->d_lock);
rcu_read_lock();
+ spin_unlock(&dentry->d_lock);
again:
parent = ACCESS_ONCE(dentry->d_parent);
spin_lock(&parent->d_lock);
---------- patch end ----------
ef53 is ext4, 9fa0 is proc, 62656572 is sysfs.
I don't know why only sysfs triggered the oops.
---------- console log on boot ----------
[ 6.987663] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null)
[ 7.071152] dracut: Mounted root filesystem /dev/sda1
[ 7.275840] random: nonblocking pool is initialized
[ 7.414446] load_policy (374) used greatest stack depth: 10832 bytes left
[ 7.417446] dracut: /sbin/load_policy: Can't load policy: No such device
[ 7.630160] dracut: Switching root
[ 8.333437] ------------[ cut here ]------------
[ 8.333737] WARNING: CPU: 1 PID: 394 at fs/dcache.c:535 shrink_dentry_list+0x388/0x400()
[ 8.334546] Modules linked in: ext4(E) jbd2(E) mbcache(E) crc16(E) sd_mod(E) crc_t10dif(E) sr_mod(E) cdrom(E) mptspi(E) mptscsih(E) mptbase(E) scsi_transport_spi(E) pata_acpi(E) ata_generic(E) ata_piix(E)
[ 8.336012] CPU: 1 PID: 394 Comm: mount Tainted: G E 3.15.0-08974-g3c81bdd-dirty #390
[ 8.337616] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
[ 8.339667] 0000000000000217 ffff88004b20bd18 ffffffff8163844d ffffffff81a23cef
[ 8.340469] 0000000000000000 ffff88004b20bd58 ffffffff81054d9c ffff880048ca6fb0
[ 8.340908] ffff880078c06eb0 ffff880048ca6eb0 ffff880048ca6fb0 ffff88004b20bdd8
[ 8.341841] Call Trace:
[ 8.342440] [<ffffffff8163844d>] dump_stack+0x51/0x6c
[ 8.343495] [<ffffffff81054d9c>] warn_slowpath_common+0x8c/0xc0
[ 8.344556] [<ffffffff81054dea>] warn_slowpath_null+0x1a/0x20
[ 8.344764] [<ffffffff811e71b8>] shrink_dentry_list+0x388/0x400
[ 8.345536] [<ffffffff811e7369>] shrink_dcache_sb+0xd9/0x120
[ 8.346501] [<ffffffff811f14fd>] ? do_remount+0x9d/0x130
[ 8.347564] [<ffffffff811cf6e2>] do_remount_sb+0x52/0x1a0
[ 8.348506] [<ffffffff811f14fd>] ? do_remount+0x9d/0x130
[ 8.349520] [<ffffffff811f1585>] do_remount+0x125/0x130
[ 8.350552] [<ffffffff811f4962>] do_mount+0x1b2/0x210
[ 8.351496] [<ffffffff811810fb>] ? strndup_user+0x5b/0x80
[ 8.352501] [<ffffffff811f4a50>] SyS_mount+0x90/0xe0
[ 8.353500] [<ffffffff816483a2>] system_call_fastpath+0x16/0x1b
[ 8.354533] ---[ end trace eddfc2138fdcf65f ]---
[ 8.355486] dentry->d_lockref.count=-128 dentry->d_sb->s_magic=9fa0
(...snipped...)
[ 8.431502] dentry->d_lockref.count=-128 dentry->d_sb->s_magic=9fa0
Welcome to CentOS
---------- console log on boot ----------
---------- console log on shutdown ----------
init: Re-executing /sbin/init
[ 76.646596] dentry->d_lockref.count=-128 dentry->d_sb->s_magic=ef53
(...snipped...)
[ 76.701837] dentry->d_lockref.count=-128 dentry->d_sb->s_magic=ef53
[ 76.718264] EXT4-fs (sda1): re-mounted. Opts: (null)
[ 76.962112] dentry->d_lockref.count=-128 dentry->d_sb->s_magic=9fa0
(...snipped...)
[ 77.100116] dentry->d_lockref.count=-128 dentry->d_sb->s_magic=9fa0
[ 77.110684] dentry->d_lockref.count=-128 dentry->d_sb->s_magic=62656572
(...snipped...)
[ 77.424319] dentry->d_lockref.count=-128 dentry->d_sb->s_magic=62656572
Please stand by while rebooting the system...
[ 77.556052] reboot: Restarting system
[ 77.556942] reboot: machine restart
---------- console log on shutdown ----------
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