From: Sasha Levin <sashal@kernel.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH AUTOSEL 6.6 15/32] debugfs: annotate debugfs handlers vs. removal with lockdep
Date: Mon, 4 Dec 2023 23:25:08 -0500 [thread overview]
Message-ID: <ZW6mJFCFIvEdrnoW@sashalap> (raw)
In-Reply-To: <1a7a8caa3fe9b4e3271239b86ebd24a41464b79f.camel@sipsolutions.net>
On Mon, Dec 04, 2023 at 09:45:55PM +0100, Johannes Berg wrote:
>On Mon, 2023-12-04 at 20:32 +0000, Sasha Levin wrote:
>> From: Johannes Berg <johannes.berg@intel.com>
>>
>> [ Upstream commit f4acfcd4deb158b96595250cc332901b282d15b0 ]
>>
>> When you take a lock in a debugfs handler but also try
>> to remove the debugfs file under that lock, things can
>> deadlock since the removal has to wait for all users
>> to finish.
>>
>> Add lockdep annotations in debugfs_file_get()/_put()
>> to catch such issues.
>>
>
>This (and the previous patch) probably got picked up as dependencies for
>the locking things, but ... we reverted this.
>
>For 6.6, _maybe_ it's worth backporting this including the revert, but
>then I'd do that only when the revert landed to have them together. But
>then you should apply all the six patches listed below _and_ the revert,
>the set as here doesn't do anything useful.
>
>However ... given that debugfs is root-only, and you have to be
>reading/writing a file _while_ disconnecting and the file is removed,
>perhaps the whole thing isn't worth backporting at all.
>
>
>
>For 6.1 and earlier, I believe it's not needed at all, so please drop
>from there all of these:
>
> - debugfs: fix automount d_fsdata usage
> - debugfs: annotate debugfs handlers vs. removal with lockdep
> - debugfs: add API to allow debugfs operations cancellation
> - wifi: cfg80211: add locked debugfs wrappers
> - wifi: mac80211: use wiphy locked debugfs helpers for agg_status
> - wifi: mac80211: use wiphy locked debugfs for sdata/link
>
>
>I'd kind of think just dropping all of these completely makes more
>sense.
Will do, thanks!
--
Thanks,
Sasha
next prev parent reply other threads:[~2023-12-05 4:25 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-04 20:32 [PATCH AUTOSEL 6.6 01/32] pinctrl: s32cc: Avoid possible string truncation Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 02/32] kunit: Warn if tests are slow Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 03/32] kunit: Reset suite counter right before running tests Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 04/32] pinctrl: lochnagar: Don't build on MIPS Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 05/32] ALSA: hda - Fix speaker and headset mic pin config for CHUWI CoreBook XPro Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 06/32] ksmbd: separately allocate ci per dentry Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 07/32] ksmbd: release interim response after sending status pending response Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 08/32] ksmbd: move setting SMB2_FLAGS_ASYNC_COMMAND and AsyncId Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 09/32] ksmbd: don't update ->op_state as OPLOCK_STATE_NONE on error Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 10/32] mptcp: fix uninit-value in mptcp_incoming_options Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 11/32] wifi: cfg80211: lock wiphy mutex for rfkill poll Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 12/32] wifi: avoid offset calculation on NULL pointer Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 13/32] wifi: mac80211: handle 320 MHz in ieee80211_ht_cap_ie_to_sta_ht_cap Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 14/32] debugfs: fix automount d_fsdata usage Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 15/32] debugfs: annotate debugfs handlers vs. removal with lockdep Sasha Levin
2023-12-04 20:45 ` Johannes Berg
2023-12-05 4:25 ` Sasha Levin [this message]
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 16/32] debugfs: add API to allow debugfs operations cancellation Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 17/32] wifi: cfg80211: add locked debugfs wrappers Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 18/32] wifi: mac80211: use wiphy locked debugfs helpers for agg_status Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 19/32] ALSA: hda: intel-nhlt: Ignore vbps when looking for DMIC 32 bps format Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 20/32] nvme-core: fix a memory leak in nvme_ns_info_from_identify() Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 21/32] io_uring: use fget/fput consistently Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 22/32] block: warn once for each partition in bio_check_ro() Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 23/32] drm/amdgpu: Do not issue gpu reset from nbio v7_9 bif interrupt Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 24/32] drm/amdkfd: Use common function for IP version check Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 25/32] drm/amd/display: update dcn315 lpddr pstate latency Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 26/32] drm/amdgpu: Fix cat debugfs amdgpu_regs_didt causes kernel null pointer Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 27/32] drm/amdkfd: Free gang_ctx_bo and wptr_bo in pqm_uninit Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 28/32] drm/amdgpu: Use another offset for GC 9.4.3 remap Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 29/32] smb: client, common: fix fortify warnings Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 30/32] Revert "drm/prime: Unexport helpers for fd/handle conversion" Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 31/32] blk-mq: don't count completed flush data request as inflight in case of quiesce Sasha Levin
2023-12-04 20:32 ` [PATCH AUTOSEL 6.6 32/32] nvme-core: check for too small lba shift Sasha Levin
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