Rename file corruption?

Hello Kernel devs,

I built a snapshot of Linus's kernel (master)

Triggered fault in EXT4 compiling LLVM/clang/Mesa:

Jun 15 12:36:41 segfault kernel: [34407.966896] Modules linked in: bnep bluetooth cpufreq_stats ebtable_filter ebtables ip6table_filter ip6_tables bridge amdkfd amd_iommu_v2 amdgpu intel_rapl x86_pkg_temp_thermal intel_powerclamp kvm_intel arc4 iwlmvm kvm coretemp snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic mac80211 uvcvideo snd_hda_intel snd_hda_codec videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 vfat snd_usb_audio irqbypass crct10dif_pclmul videobuf2_core snd_soc_rt5640 snd_soc_rl6231 i2c_algo_bit snd_soc_core snd_usbmidi_lib snd_compress crc32_pclmul videodev ghash_clmulni_intel fat ttm snd_hda_core snd_pcm_dmaengine ac97_bus snd_rawmidi snd_hwdep snd_seq intel_cstate drm_kms_helper intel_uncore drm dell_wmi mei_wdt sparse_keymap iwlwifi snd_seq_device media snd_pcm iTCO_wdt dell_laptop dell_smbios iTCO_vendor_support snd_timer dcdbas ppdev dell_smm_hwmon cfg80211 snd pcspkr joydev elan_i2c ie31200_edac wmi i2c_designware_platform edac_core mei_me shpchp dw_dmac parport_pc parport mei i2c_designware_core lpc_ich video snd_soc_sst_acpi snd_soc_sst_match soundcore dw_dmac_core i2c_i801 tpm_tis spi_pxa2xx_platform tpm dell_rbtn rfkill dell_smo8800 nfsd auth_rpcgss nfs_acl lockd grace sunrpc binfmt_misc 8021q garp stp llc netconsole mrp sdhci_pci crc32c_intel sdhci_acpi sdhci serio_raw mmc_core fjes i2c_hid e1000e ptp pps_core
Jun 15 12:36:41 segfault kernel: [34407.973782] CPU: 3 PID: 12388 Comm: gcc Not tainted 4.7.0-rc3+ #1
Jun 15 12:36:41 segfault kernel: [34407.974026] Hardware name: Dell Inc. Precision M6800/05NG6V, BIOS A16 12/01/2015
Jun 15 12:36:41 segfault kernel: [34407.974289]  0000000000000286 0000000040a52c61 ffff88073fe9bc90 ffffffff813d07af
Jun 15 12:36:41 segfault kernel: [34407.974576]  0000000000000000 0000000000000000 ffff88073fe9bcd0 ffffffff8109f53b
Jun 15 12:36:41 segfault kernel: [34407.974864]  000001183fe9bcf8 ffff880487740928 ffff880487740928 0000000000000000
Jun 15 12:36:41 segfault kernel: [34407.975150] Call Trace:
Jun 15 12:36:41 segfault kernel: [34407.975246]  [<ffffffff813d07af>] dump_stack+0x63/0x84
Jun 15 12:36:41 segfault kernel: [34407.975432]  [<ffffffff8109f53b>] __warn+0xcb/0xf0
Jun 15 12:36:41 segfault kernel: [34407.975605]  [<ffffffff8109f66d>] warn_slowpath_null+0x1d/0x20
Jun 15 12:36:41 segfault kernel: [34407.975817]  [<ffffffff8125b76e>] drop_nlink+0x3e/0x50
Jun 15 12:36:41 segfault kernel: [34407.976068]  [<ffffffff812e2080>] ext4_rename+0x530/0x910
Jun 15 12:36:41 segfault kernel: [34407.976332]  [<ffffffff81249a7e>] ? terminate_walk+0x8e/0xf0
Jun 15 12:36:41 segfault kernel: [34407.976607]  [<ffffffff812e247d>] ext4_rename2+0x1d/0x30
Jun 15 12:36:41 segfault kernel: [34407.976866]  [<ffffffff8124dcd3>] vfs_rename+0x5a3/0x900
Jun 15 12:36:41 segfault kernel: [34407.977125]  [<ffffffff8124ad01>] ? trailing_symlink+0x181/0x220
Jun 15 12:36:41 segfault kernel: [34407.977416]  [<ffffffff81252337>] SyS_rename+0x3a7/0x3d0
Jun 15 12:36:41 segfault kernel: [34407.977679]  [<ffffffff817d88b2>] entry_SYSCALL_64_fastpath+0x1a/0xa4
Jun 15 12:36:41 segfault kernel: [34407.978014] ---[ end trace 812bc2d188b90844 ]---
Jun 15 12:36:45 segfault kernel: [34412.076658] ------------[ cut here ]------------
Jun 15 12:36:45 segfault kernel: [34412.076897] WARNING: CPU: 2 PID: 13368 at fs/inode.c:280 drop_nlink+0x3e/0x50

On shutdown, had inode corruption, rebooted had to fsck to repair.

Thanks,
Shawn

We see somewhat similar rename corruption on XFS, also under heavy compile workloads. The reporters have already ruled out the XFS changes from the 4.7 merge window, so this looks a lot like the VFS changes that went into this merge window.

Can that be triggered on 4e82901 + cherry-pick of e7d6ef979? Same for 9f541801 + e7d6ef979?