kernel/linux.git/sound/core/info.c, branch v6.6.141

ALSA: info: Fix potential deadlock at disconnection

2023-11-28T17:20:10+00:00

commit c7a60651953359f98dbf24b43e1bf561e1573ed4 upstream. As reported recently, ALSA core info helper may cause a deadlock at the forced device disconnection during the procfs operation. The proc_remove() (that is called from the snd_card_disconnect() helper) has a synchronization of the pending procfs accesses via wait_for_completion(). Meanwhile, ALSA procfs helper takes the global mutex_lock(&info_mutex) at both the proc_open callback and snd_card_info_disconnect() helper. Since the proc_open can't finish due to the mutex lock, wait_for_completion() never returns, either, hence it deadlocks. TASK#1 TASK#2 proc_reg_open() takes use_pde() snd_info_text_entry_open() snd_card_disconnect() snd_info_card_disconnect() takes mutex_lock(&info_mutex) proc_remove() wait_for_completion(unused_pde) ... waiting task#1 closes mutex_lock(&info_mutex) => DEADLOCK This patch is a workaround for avoiding the deadlock scenario above. The basic strategy is to move proc_remove() call outside the mutex lock. proc_remove() can work gracefully without extra locking, and it can delete the tree recursively alone. So, we call proc_remove() at snd_info_card_disconnection() at first, then delete the rest resources recursively within the info_mutex lock. After the change, the function snd_info_disconnect() doesn't do disconnection by itself any longer, but it merely clears the procfs pointer. So rename the function to snd_info_clear_entries() for avoiding confusion. The similar change is applied to snd_info_free_entry(), too. Since the proc_remove() is called only conditionally with the non-NULL entry->p, it's skipped after the snd_info_clear_entries() call. Reported-by: Shinhyung Kang Closes: https://lore.kernel.org/r/664457955.21699345385931.JavaMail.epsvc@epcpadp4 Reviewed-by: Jaroslav Kysela Cc: Link: https://lore.kernel.org/r/20231109141954.4283-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: info: Fix llseek return value when using callback

2022-08-17T13:13:30+00:00

When using callback there was a flow of ret = -EINVAL if (callback) { offset = callback(); goto out; } ... offset = some other value in case of no callback; ret = offset; out: return ret; which causes the snd_info_entry_llseek() to return -EINVAL when there is callback handler. Fix this by setting "ret" directly to callback return value before jumping to "out". Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode") Signed-off-by: Amadeusz Sławiński Cc: Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com Signed-off-by: Takashi Iwai

ALSA: core: Fix missing return value comments for kernel docs

2022-07-13T11:42:38+00:00

Each kernel doc comment expects the definition of the return value in a proper format. This patch adds or fixes the missing entries for the remaining ALSA core API functions. Link: https://lore.kernel.org/r/20220713104759.4365-8-tiwai@suse.de Signed-off-by: Takashi Iwai

proc: remove PDE_DATA() completely

2022-01-22T06:33:37+00:00

Remove PDE_DATA() completely and replace it with pde_data(). [akpm@linux-foundation.org: fix naming clash in drivers/nubus/proc.c] [akpm@linux-foundation.org: now fix it properly] Link: https://lkml.kernel.org/r/20211124081956.87711-2-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Christian Brauner Cc: Alexey Dobriyan Cc: Alexey Gladkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

isystem: trim/fixup stdarg.h and other headers

2021-08-19T00:02:55+00:00

Delete/fixup few includes in anticipation of global -isystem compile option removal. Note: crypto/aegis128-neon-inner.c keeps due to redefinition of uintptr_t error (one definition comes from , another from ). Signed-off-by: Alexey Dobriyan Signed-off-by: Masahiro Yamada

ALSA: info: Drop WARN_ON() from buffer NULL sanity check

2020-07-17T08:59:38+00:00

snd_info_get_line() has a sanity check of NULL buffer -- both buffer itself being NULL and buffer->buffer being NULL. Basically both checks are valid and necessary, but the problem is that it's with snd_BUG_ON() macro that triggers WARN_ON(). The latter condition (NULL buffer->buffer) can be met arbitrarily by user since the buffer is allocated at the first write, so it means that user can trigger WARN_ON() at will. This patch addresses it by simply moving buffer->buffer NULL check out of snd_BUG_ON() so that spurious WARNING is no longer triggered. Reported-by: syzbot+e42d0746c3c3699b6061@syzkaller.appspotmail.com Cc: Link: https://lore.kernel.org/r/20200717084023.5928-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: info: remove redundant assignment to variable c

2020-02-10T07:30:02+00:00

Variable c is being assigned with the value -1 that is never read, it is assigned a new value in a following while-loop. The assignment is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King Link: https://lore.kernel.org/r/20200208224206.38540-1-colin.king@canonical.com Signed-off-by: Takashi Iwai

proc: convert everything to "struct proc_ops"

2020-02-04T03:05:26+00:00

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in seq_file.h. Conversion rule is: llseek => proc_lseek unlocked_ioctl => proc_ioctl xxx => proc_xxx delete ".owner = THIS_MODULE" line [akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c] [sfr@canb.auug.org.au: fix kernel/sched/psi.c] Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2 Signed-off-by: Alexey Dobriyan Signed-off-by: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ALSA: info: More constifications

2020-01-05T15:14:57+00:00

Apply const prefix to the string array and its callers. Just for minor optimization and no functional changes. Link: https://lore.kernel.org/r/20200105144823.29547-39-tiwai@suse.de Signed-off-by: Takashi Iwai

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman