From: Johannes Berg <johannes@sipsolutions.net>
To: Sasha Levin <sashal@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH AUTOSEL 6.6 15/32] debugfs: annotate debugfs handlers vs. removal with lockdep
Date: Mon, 04 Dec 2023 21:45:55 +0100 [thread overview]
Message-ID: <1a7a8caa3fe9b4e3271239b86ebd24a41464b79f.camel@sipsolutions.net> (raw)
In-Reply-To: <20231204203317.2092321-15-sashal@kernel.org>
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.
johannes
next prev parent reply other threads:[~2023-12-04 20:46 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 [this message]
2023-12-05 4:25 ` Sasha Levin
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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