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2018-01-11ALSA: seq: Make ioctls race-freeTakashi Iwai2-0/+4
The ALSA sequencer ioctls have no protection against racy calls while the concurrent operations may lead to interfere with each other. As reported recently, for example, the concurrent calls of setting client pool with a combination of write calls may lead to either the unkillable dead-lock or UAF. As a slightly big hammer solution, this patch introduces the mutex to make each ioctl exclusive. Although this may reduce performance via parallel ioctl calls, usually it's not demanded for sequencer usages, hence it should be negligible. Reported-by: Luo Quan <a4651386@163.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-01-11ALSA: pcm: Remove yet superfluous WARN_ON()Takashi Iwai1-1/+0
muldiv32() contains a snd_BUG_ON() (which is morphed as WARN_ON() with debug option) for checking the case of 0 / 0. This would be helpful if this happens only as a logical error; however, since the hw refine is performed with any data set provided by user, the inconsistent values that can trigger such a condition might be passed easily. Actually, syzbot caught this by passing some zero'ed old hw_params ioctl. So, having snd_BUG_ON() there is simply superfluous and rather harmful to give unnecessary confusions. Let's get rid of it. Reported-by: syzbot+7e6ee55011deeebce15d@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-01-08ALSA: pcm: Allow aborting mutex lock at OSS read/write loopsTakashi Iwai1-15/+21
PCM OSS read/write loops keep taking the mutex lock for the whole read/write, and this might take very long when the exceptionally high amount of data is given. Also, since it invokes with mutex_lock(), the concurrent read/write becomes unbreakable. This patch tries to address these issues by replacing mutex_lock() with mutex_lock_interruptible(), and also splits / re-takes the lock at each read/write period chunk, so that it can switch the context more finely if requested. Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-01-08ALSA: pcm: Abort properly at pending signal in OSS read/write loopsTakashi Iwai1-0/+8
The loops for read and write in PCM OSS emulation have no proper check of pending signals, and they keep processing even after user tries to break. This results in a very long delay, often seen as RCU stall when a huge unprocessed bytes remain queued. The bug could be easily triggered by syzkaller. As a simple workaround, this patch adds the proper check of pending signals and aborts the loop appropriately. Reported-by: syzbot+993cb4cfcbbff3947c21@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-01-05ALSA: pcm: Workaround for weird PulseAudio behavior on rewind errorTakashi Iwai1-2/+7
The commit 9027c4639ef1 ("ALSA: pcm: Call ack() whenever appl_ptr is updated") introduced the possible error code returned from the PCM rewind ioctl. Basically the change was for handling the indirect PCM more correctly, but ironically, it caused rather a side-effect: PulseAudio gets pissed off when receiving an error from rewind, throws everything away and stops processing further, resulting in the silence. It's clearly a failure in the application side, so the best would be to fix that bug in PA. OTOH, PA is mostly the only user of the rewind feature, so it's not good to slap the sole customer. This patch tries to mitigate the situation: instead of returning an error, now the rewind ioctl returns zero when the driver can't rewind. It indicates that no rewind was performed, so the behavior is consistent, at least. Fixes: 9027c4639ef1 ("ALSA: pcm: Call ack() whenever appl_ptr is updated") Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-01-04ALSA: pcm: Add missing error checks in OSS emulation plugin builderTakashi Iwai1-3/+11
In the OSS emulation plugin builder where the frame size is parsed in the plugin chain, some places miss the possible errors returned from the plugin src_ or dst_frames callback. This patch papers over such places. Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-01-02ALSA: pcm: Remove incorrect snd_BUG_ON() usagesTakashi Iwai2-3/+2
syzkaller triggered kernel warnings through PCM OSS emulation at closing a stream: WARNING: CPU: 0 PID: 3502 at sound/core/pcm_lib.c:1635 snd_pcm_hw_param_first+0x289/0x690 sound/core/pcm_lib.c:1635 Call Trace: .... snd_pcm_hw_param_near.constprop.27+0x78d/0x9a0 sound/core/oss/pcm_oss.c:457 snd_pcm_oss_change_params+0x17d3/0x3720 sound/core/oss/pcm_oss.c:969 snd_pcm_oss_make_ready+0xaa/0x130 sound/core/oss/pcm_oss.c:1128 snd_pcm_oss_sync+0x257/0x830 sound/core/oss/pcm_oss.c:1638 snd_pcm_oss_release+0x20b/0x280 sound/core/oss/pcm_oss.c:2431 __fput+0x327/0x7e0 fs/file_table.c:210 .... This happens while it tries to open and set up the aloop device concurrently. The warning above (invoked from snd_BUG_ON() macro) is to detect the unexpected logical error where snd_pcm_hw_refine() call shouldn't fail. The theory is true for the case where the hw_params config rules are static. But for an aloop device, the hw_params rule condition does vary dynamically depending on the connected target; when another device is opened and changes the parameters, the device connected in another side is also affected, and it caused the error from snd_pcm_hw_refine(). That is, the simplest "solution" for this is to remove the incorrect assumption of static rules, and treat such an error as a normal error path. As there are a couple of other places using snd_BUG_ON() incorrectly, this patch removes these spurious snd_BUG_ON() calls. Reported-by: syzbot+6f11c7e2a1b91d466432@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-12-14ALSA: rawmidi: Avoid racy info ioctl via ctl deviceTakashi Iwai1-3/+12
The rawmidi also allows to obtaining the information via ioctl of ctl API. It means that user can issue an ioctl to the rawmidi device even when it's being removed as long as the control device is present. Although the code has some protection via the global register_mutex, its range is limited to the search of the corresponding rawmidi object, and the mutex is already unlocked at accessing the rawmidi object. This may lead to a use-after-free. For avoiding it, this patch widens the application of register_mutex to the whole snd_rawmidi_info_select() function. We have another mutex per rawmidi object, but this operation isn't very hot path, so it shouldn't matter from the performance POV. Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-12-05ALSA: pcm: prevent UAF in snd_pcm_infoRobb Glasser1-0/+2
When the device descriptor is closed, the `substream->runtime` pointer is freed. But another thread may be in the ioctl handler, case SNDRV_CTL_IOCTL_PCM_INFO. This case calls snd_pcm_info_user() which calls snd_pcm_info() which accesses the now freed `substream->runtime`. Note: this fixes CVE-2017-0861 Signed-off-by: Robb Glasser <rglasser@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-11-30ALSA: seq: Remove spurious WARN_ON() at timer checkTakashi Iwai1-1/+1
The use of snd_BUG_ON() in ALSA sequencer timer may lead to a spurious WARN_ON() when a slave timer is deployed as its backend and a corresponding master timer stops meanwhile. The symptom was triggered by syzkaller spontaneously. Since the NULL timer is valid there, rip off snd_BUG_ON(). Reported-by: syzbot <syzkaller@googlegroups.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-11-22ALSA: hda - Fix yet remaining issue with vmaster 0dB initializationTakashi Iwai1-2/+4
The previous fix for addressing the breakage in vmaster slave initialization, commit a91d66129fb9 ("ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal"), introduced a new helper to process over each slave kctl. However, this helper passes only the original kctl, not the virtual slave kctl. As a result, HD-audio driver (which is the only user so far) couldn't initialize the slave correctly because it's trying to update the value directly with the original kctl, not with the mapped kctl. This patch fixes the situation again by passing both the mapped slaved and original slave kctls to the function. Luckily there is a single caller as of now, so changing the call signature is no big matter. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=197959 Fixes: a91d66129fb9 ("ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal") Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-11-21ALSA: timer: Remove kernel warning at compat ioctl error pathsTakashi Iwai1-6/+6
Some timer compat ioctls have NULL checks of timer instance with snd_BUG_ON() that bring up WARN_ON() when the debug option is set. Actually the condition can be met in the normal situation and it's confusing and bad to spew kernel warnings with stack trace there. Let's remove snd_BUG_ON() invocation and replace with the simple checks. Also, correct the error code to EBADFD to follow the native ioctl error handling. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-11-21ALSA: pcm: update tstamp only if audio_tstamp changedHenrik Eriksson1-2/+4
commit 3179f6200188 ("ALSA: core: add .get_time_info") had a side effect of changing the behaviour of the PCM runtime tstamp. Prior to this change tstamp was not updated by snd_pcm_update_hw_ptr0() unless the hw_ptr had moved, after this change tstamp was always updated. For an application using alsa-lib, doing snd_pcm_readi() followed by snd_pcm_status() to estimate the age of the read samples by subtracting status->avail * [sample rate] from status->tstamp this change degraded the accuracy of the estimate on devices where the pcm hw does not provide a granular hw_ptr, e.g., devices using soc-generic-dmaengine-pcm.c and a dma-engine with residue_granularity DMA_RESIDUE_GRANULARITY_DESCRIPTOR. The accuracy of the estimate depended on the latency between the PCM hw completing a period and the driver called snd_pcm_period_elapsed() to notify ALSA core, typically determined by interrupt handling latency. After the change the accuracy of the estimate depended on the latency between the PCM hw completing a period and the application calling snd_pcm_status(), determined by the scheduling of the application process. The maximum error of the estimate is one period length in both cases, but the error average and variance is smaller when it depends on interrupt latency. Instead of always updating tstamp, update it only if audio_tstamp changed. Fixes: 3179f6200188 ("ALSA: core: add .get_time_info") Suggested-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Signed-off-by: Henrik Eriksson <henrik.eriksson@axis.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-11-13Merge tag 'asoc-v4.15' of ↵Takashi Iwai6-0/+6
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus ASoC: Updates for v4.15 The biggest thing this release has been the conversion of the AC98 bus to the driver model, that's been a long time coming so thanks to Robert Jarzmik for his dedication there. Due to there being some AC97 MFD there's a few fairly large changes in input and the MFD layer, mainly to the wm97xx driver. There's also some drivers/drm changes to support the new AMD Stoney platform, these are shared with the DRM subsystem and should be being merged via both. Within the subsystem the overwhelming bulk of the changes is in the Intel drivers which continue to need lots of cleanups and fixes, this release they've also gained support for their open source firmware. There's also some large changs in the core as Morimoto-san continues to mirror operations into the component level in preparation for conversion of drivers to that. - The AC97 bus has finally caught up with the driver model thanks to some dedicated and persistent work from Robert Jarzmik. - Continued work from Morimoto-san on moving us towards being able to use components for everything. - Lots of cleanups for the Intel platform code, including support for their open source audio firmware. - Support for scaling MCLK with sample rate in simple-card. - Support for AMD Stoney platform.
2017-11-13Merge branch 'for-next' into for-linusTakashi Iwai8-16/+59
Pull 4.15 updates to take over the previous urgent fixes. Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-11-07ALSA: seq: Fix OSS sysex delivery in OSS emulationTakashi Iwai3-3/+32
The SYSEX event delivery in OSS sequencer emulation assumed that the event is encoded in the variable-length data with the straight buffering. This was the normal behavior in the past, but during the development, the chained buffers were introduced for carrying more data, while the OSS code was left intact. As a result, when a SYSEX event with the chained buffer data is passed to OSS sequencer port, it may end up with the wrong memory access, as if it were having a too large buffer. This patch addresses the bug, by applying the buffer data expansion by the generic snd_seq_dump_var_event() helper function. Reported-by: syzbot <syzkaller@googlegroups.com> Reported-by: Mark Salyzyn <salyzyn@android.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-11-06ALSA: timer: Limit max instances per timerTakashi Iwai2-13/+55
Currently we allow unlimited number of timer instances, and it may bring the system hogging way too much CPU when too many timer instances are opened and processed concurrently. This may end up with a soft-lockup report as triggered by syzkaller, especially when hrtimer backend is deployed. Since such insane number of instances aren't demanded by the normal use case of ALSA sequencer and it merely opens a risk only for abuse, this patch introduces the upper limit for the number of instances per timer backend. As default, it's set to 1000, but for the fine-grained timer like hrtimer, it's set to 100. Reported-by: syzbot Tested-by: Jérôme Glisse <jglisse@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-11-02Merge tag 'spdx_identifiers-4.14-rc8' of ↵Linus Torvalds6-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull initial SPDX identifiers from Greg KH: "License cleanup: add SPDX license identifiers to some files Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" * tag 'spdx_identifiers-4.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: License cleanup: add SPDX license identifier to uapi header files with a license License cleanup: add SPDX license identifier to uapi header files with no license License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman6-0/+6
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-31ALSA: seq: Fix nested rwsem annotation for lockdep splatTakashi Iwai1-1/+1
syzkaller reported the lockdep splat due to the possible deadlock of grp->list_mutex of each sequencer client object. Actually this is rather a false-positive report due to the missing nested lock annotations. The sequencer client may deliver the event directly to another client which takes another own lock. For addressing this issue, this patch replaces the simple down_read() with down_read_nested(). As a lock subclass, the already existing "hop" can be re-used, which indicates the depth of the call. Reference: http://lkml.kernel.org/r/089e082686ac9b482e055c832617@google.com Reported-by: syzbot <bot+7feb8de6b4d6bf810cf098bef942cc387e79d0ad@syzkaller.appspotmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-31ALSA: timer: Add missing mutex lock for compat ioctlsTakashi Iwai1-2/+15
The races among ioctl and other operations were protected by the commit af368027a49a ("ALSA: timer: Fix race among timer ioctls") and later fixes, but one code path was forgotten in the scenario: the 32bit compat ioctl. As syzkaller recently spotted, a very similar use-after-free may happen with the combination of compat ioctls. The fix is simply to apply the same ioctl_lock to the compat_ioctl callback, too. Fixes: af368027a49a ("ALSA: timer: Fix race among timer ioctls") Reference: http://lkml.kernel.org/r/089e082686ac9b482e055c832617@google.com Reported-by: syzbot <bot+e5f3c9783e7048a74233054febbe9f1bdf54b6da@syzkaller.appspotmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-30ALSA: fix kernel-doc build warningRandy Dunlap1-1/+1
Fix kernel-doc build error. A symbol that ends with an underscore character ('_') has special meaning in reST (reStructuredText), so add a '*' to prevent this error and to indicate that there are several of these values to choose from. ../sound/core/jack.c:312: ERROR: Unknown target name: "snd_jack_btn". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-24Merge branch 'topic/card-disconnect' into for-nextTakashi Iwai2-8/+44
Pull snd_card_disconnect_sync() extension for ASoC hot-unplug support. Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-18ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removalTakashi Iwai1-0/+31
The commit 99b5c5bb9a54 ("ALSA: hda - Remove the use of set_fs()") converted the get_kctl_0dB_offset() call for killing set_fs() usage in HD-audio codec code. The conversion assumed that the TLV callback used in HD-audio code is only snd_hda_mixer_amp() and applies the TLV calculation locally. Although this assumption is correct, and all slave kctls are actually with that callback, the current code is still utterly buggy; it doesn't hit this condition and falls back to the next check. It's because the function gets called after adding slave kctls to vmaster. By assigning a slave kctl, the slave kctl object is faked inside vmaster code, and the whole kctl ops are overridden. Thus the callback op points to a different value from what we've assumed. More badly, as reported by the KERNEXEC and UDEREF features of PaX, the code flow turns into the unexpected pitfall. The next fallback check is SNDRV_CTL_ELEM_ACCESS_TLV_READ access bit, and this always hits for each kctl with TLV. Then it evaluates the callback function pointer wrongly as if it were a TLV array. Although currently its side-effect is fairly limited, this incorrect reference may lead to an unpleasant result. For addressing the regression, this patch introduces a new helper to vmaster code, snd_ctl_apply_vmaster_slaves(). This works similarly like the existing map_slaves() in hda_codec.c: it loops over the slave list of the given master, and applies the given function to each slave. Then the initializer function receives the right kctl object and we can compare the correct pointer instead of the faked one. Also, for catching the similar breakage in future, give an error message when the unexpected TLV callback is found and bail out immediately. Fixes: 99b5c5bb9a54 ("ALSA: hda - Remove the use of set_fs()") Reported-by: PaX Team <pageexec@freemail.hu> Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-18ALSA: pcm: Forcibly stop at disconnect callbackTakashi Iwai1-0/+4
So far we assumed that each driver implements the hotplug PCM handling properly, e.g. dealing with the pending PCM stream at disconnect callback. But most codes don't care, and it eventually leaves the PCM stream inconsistent state when an abrupt disconnection like sysfs unbind happens. This patch is simple but a big-hammer solution: invoke snd_pcm_stop() at the common PCM disconnect callback always when the stream is running. Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-18ALSA: pcm: Don't call register and disconnect callbacks for internal PCMTakashi Iwai1-8/+8
The internal PCM (aka DPCM backend PCM) doesn't need any registration procedure, thus currently we bail out immediately at dev_register callback. Similarly, its counterpart, dev_disconnect callback, is superfluous for the internal PCM. For simplifying and avoiding the conflicting disconnect call for internal PCM objects, this patch drops dev_register and dev_disconnect callbacks for the internal ops. The only uncertain thing by this action is whether skipping the PCM state change to SNDRV_PCM_STATE_DISCONNECT for the internal PCM is mandatory. Looking through the current implementations, this doesn't look so, hence dropping the whole dev_disconnect would make more sense. Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-18ALSA: seq: Enable 'use' locking in all configurationsBen Hutchings2-16/+0
The 'use' locking macros are no-ops if neither SMP or SND_DEBUG is enabled. This might once have been OK in non-preemptible configurations, but even in that case snd_seq_read() may sleep while relying on a 'use' lock. So always use the proper implementations. Cc: stable@vger.kernel.org Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-17Merge branch 'for-linus' into for-nextTakashi Iwai2-3/+10
Back-merge for applying the timer API conversion patch for line6 driver that conflicts with the recent fix in upstream. Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-16ALSA: pcm: remove redundant variable runtimeColin Ian King1-2/+0
An earlier commit removed the access to variable runtime and we are now left with unused variable that is redundant, so remove it. Cleans up the clang warning: Value stored to 'runtime' is never read Fixes: e11f0f90a626 ("ALSA: pcm: remove SNDRV_PCM_IOCTL1_INFO internal command") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-11ALSA: add snd_card_disconnect_sync()Takashi Iwai1-0/+32
In case of user unbind ALSA driver during playing back / capturing, each driver needs to stop and remove it correctly. One note here is that we can't cancel from remove function in such case, because unbind operation doesn't check return value from remove function. So, we *must* stop and remove in this case. For this purpose, we need to sync (= wait) until the all top-level operations are canceled at remove function. For example, snd_card_free() processes the disconnection procedure at first, then waits for the completion. That's how the hot-unplug works safely. It's implemented, at least, in the top-level driver removal. Now for the lower level driver, we need a similar strategy. Notify to the toplevel for hot-unplug (disconnect in ALSA), and sync with the stop operation, then continue the rest of its own remove procedure. This patch adds snd_card_disconnect_sync(), and driver can use it from remove function. Note: the "lower level" driver here refers to a middle layer driver (e.g. ASoC components) that can be unbound freely during operation. Most of legacy ALSA helper drivers don't have such a problem because they can't be unbound. Note#2: snd_card_disconnect_sync() merely calls snd_card_disconnect() and syncs with closing all pending files. It takes only the files opened by user-space into account, and doesn't care about object refcounts. (The latter is handled by snd_card_free() completion call, BTW.) Also, the function doesn't free resources by itself. Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-11ALSA: seq: Fix use-after-free at creating a portTakashi Iwai2-3/+10
There is a potential race window opened at creating and deleting a port via ioctl, as spotted by fuzzing. snd_seq_create_port() creates a port object and returns its pointer, but it doesn't take the refcount, thus it can be deleted immediately by another thread. Meanwhile, snd_seq_ioctl_create_port() still calls the function snd_seq_system_client_ev_port_start() with the created port object that is being deleted, and this triggers use-after-free like: BUG: KASAN: use-after-free in snd_seq_ioctl_create_port+0x504/0x630 [snd_seq] at addr ffff8801f2241cb1 ============================================================================= BUG kmalloc-512 (Tainted: G B ): kasan: bad access detected ----------------------------------------------------------------------------- INFO: Allocated in snd_seq_create_port+0x94/0x9b0 [snd_seq] age=1 cpu=3 pid=4511 ___slab_alloc+0x425/0x460 __slab_alloc+0x20/0x40 kmem_cache_alloc_trace+0x150/0x190 snd_seq_create_port+0x94/0x9b0 [snd_seq] snd_seq_ioctl_create_port+0xd1/0x630 [snd_seq] snd_seq_do_ioctl+0x11c/0x190 [snd_seq] snd_seq_ioctl+0x40/0x80 [snd_seq] do_vfs_ioctl+0x54b/0xda0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x16/0x75 INFO: Freed in port_delete+0x136/0x1a0 [snd_seq] age=1 cpu=2 pid=4717 __slab_free+0x204/0x310 kfree+0x15f/0x180 port_delete+0x136/0x1a0 [snd_seq] snd_seq_delete_port+0x235/0x350 [snd_seq] snd_seq_ioctl_delete_port+0xc8/0x180 [snd_seq] snd_seq_do_ioctl+0x11c/0x190 [snd_seq] snd_seq_ioctl+0x40/0x80 [snd_seq] do_vfs_ioctl+0x54b/0xda0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x16/0x75 Call Trace: [<ffffffff81b03781>] dump_stack+0x63/0x82 [<ffffffff81531b3b>] print_trailer+0xfb/0x160 [<ffffffff81536db4>] object_err+0x34/0x40 [<ffffffff815392d3>] kasan_report.part.2+0x223/0x520 [<ffffffffa07aadf4>] ? snd_seq_ioctl_create_port+0x504/0x630 [snd_seq] [<ffffffff815395fe>] __asan_report_load1_noabort+0x2e/0x30 [<ffffffffa07aadf4>] snd_seq_ioctl_create_port+0x504/0x630 [snd_seq] [<ffffffffa07aa8f0>] ? snd_seq_ioctl_delete_port+0x180/0x180 [snd_seq] [<ffffffff8136be50>] ? taskstats_exit+0xbc0/0xbc0 [<ffffffffa07abc5c>] snd_seq_do_ioctl+0x11c/0x190 [snd_seq] [<ffffffffa07abd10>] snd_seq_ioctl+0x40/0x80 [snd_seq] [<ffffffff8136d433>] ? acct_account_cputime+0x63/0x80 [<ffffffff815b515b>] do_vfs_ioctl+0x54b/0xda0 ..... We may fix this in a few different ways, and in this patch, it's fixed simply by taking the refcount properly at snd_seq_create_port() and letting the caller unref the object after use. Also, there is another potential use-after-free by sprintf() call in snd_seq_create_port(), and this is moved inside the lock. This fix covers CVE-2017-15265. Reported-and-tested-by: Michael23 Yu <ycqzsy@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-10ALSA: seq: Add sanity check for user-space pointer deliveryTakashi Iwai1-0/+4
The sequencer event may contain a user-space pointer with its SNDRV_SEQ_EXT_USRPTR bit, and we assure that its delivery is limited with non-atomic mode. Otherwise the copy_from_user() may hit the fault and cause a problem. Although the core code doesn't set such a flag (only set at snd_seq_write()), any wild driver may set it mistakenly and lead to an unexpected crash. This patch adds a sanity check of such events at the delivery core code to filter out the invalid invocation in the atomic mode. Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-09Merge branch 'for-linus' into for-nextTakashi Iwai3-10/+21
2017-10-09ALSA: seq: Fix copy_from_user() call inside lockTakashi Iwai1-8/+19
The event handler in the virmidi sequencer code takes a read-lock for the linked list traverse, while it's calling snd_seq_dump_var_event() in the loop. The latter function may expand the user-space data depending on the event type. It eventually invokes copy_from_user(), which might be a potential dead-lock. The sequencer core guarantees that the user-space data is passed only with atomic=0 argument, but snd_virmidi_dev_receive_event() ignores it and always takes read-lock(). For avoiding the problem above, this patch introduces rwsem for non-atomic case, while keeping rwlock for atomic case. Also while we're at it: the superfluous irq flags is dropped in snd_virmidi_input_open(). Reported-by: Jia-Ju Bai <baijiaju1990@163.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-10-05Merge branch 'topic/timer-api' into for-nextTakashi Iwai1-4/+7
2017-10-05ALSA: timer: Convert timers to use timer_setup()Kees Cook1-4/+7
In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. This adds a pointer back to struct snd_timer. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-09-22ALSA: pcm: Fix structure definition for X32 ABIBaolin Wang1-0/+1
X32 ABI uses the 64bit timespec in addition to 64bit alignment of 64bit values. We have added compat ABI for these ioctls, but this patch adds one missing padding into 'struct snd_pcm_mmap_status_x32' to fix incompatibilities. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-09-19ALSA: hrtimer: make hrtimer_hw const and __initconstBhumika Goyal1-1/+1
Make this const as it is only used during a copy operation. Also, make it __initconst as it is only used during the init phase and after this it is not referenced anywhere. Signed-off-by: Bhumika Goyal <bhumirks@gmail.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-09-18ALSA: compress: Remove unused variableGuneshwor Singh1-2/+1
Commit 04c5d5a430fc ("ALSA: compress: Embed struct device") removed the statement that used 'str' but didn't remove the variable itself. So remove it. [Adding stable to Cc since pr_debug() may refer to the uninitialized buffer -- tiwai] Fixes: 04c5d5a430fc ("ALSA: compress: Embed struct device") Signed-off-by: Guneshwor Singh <guneshwor.o.singh@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-09-18ALSA: hwdep: prevent a harmless shift wrapping bugDan Carpenter1-0/+2
The "info.index" variable represents a bit in hw->dsp_loaded which is an unsigned int. If it's higher than 31 we hit a shift wrapping bug. This seems harmless, but I wanted to silence the static checker warning. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-09-12ALSA: seq: Cancel pending autoload work at unbinding deviceTakashi Iwai1-0/+3
ALSA sequencer core has a mechanism to load the enumerated devices automatically, and it's performed in an off-load work. This seems causing some race when a sequencer is removed while the pending autoload work is running. As syzkaller spotted, it may lead to some use-after-free: BUG: KASAN: use-after-free in snd_rawmidi_dev_seq_free+0x69/0x70 sound/core/rawmidi.c:1617 Write of size 8 at addr ffff88006c611d90 by task kworker/2:1/567 CPU: 2 PID: 567 Comm: kworker/2:1 Not tainted 4.13.0+ #29 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: events autoload_drivers Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x192/0x22c lib/dump_stack.c:52 print_address_description+0x78/0x280 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x230/0x340 mm/kasan/report.c:409 __asan_report_store8_noabort+0x1c/0x20 mm/kasan/report.c:435 snd_rawmidi_dev_seq_free+0x69/0x70 sound/core/rawmidi.c:1617 snd_seq_dev_release+0x4f/0x70 sound/core/seq_device.c:192 device_release+0x13f/0x210 drivers/base/core.c:814 kobject_cleanup lib/kobject.c:648 [inline] kobject_release lib/kobject.c:677 [inline] kref_put include/linux/kref.h:70 [inline] kobject_put+0x145/0x240 lib/kobject.c:694 put_device+0x25/0x30 drivers/base/core.c:1799 klist_devices_put+0x36/0x40 drivers/base/bus.c:827 klist_next+0x264/0x4a0 lib/klist.c:403 next_device drivers/base/bus.c:270 [inline] bus_for_each_dev+0x17e/0x210 drivers/base/bus.c:312 autoload_drivers+0x3b/0x50 sound/core/seq_device.c:117 process_one_work+0x9fb/0x1570 kernel/workqueue.c:2097 worker_thread+0x1e4/0x1350 kernel/workqueue.c:2231 kthread+0x324/0x3f0 kernel/kthread.c:231 ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425 The fix is simply to assure canceling the autoload work at removing the device. Reported-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-09-07ALSA: core: Use %pS printk format for direct addressesHelge Deller1-2/+2
The debug functions uses wrongly the %pF instead of the %pS printk format specifier for printing symbols for the address returned by _builtin_return_address(0). Fix it for the ia64, ppc64 and parisc64 architectures. Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-08-30ALSA: pcm: Unify ioctl functions for playback and capture streamsTakashi Iwai2-183/+105
Some ioctl functions are implemented individually for both playback and capture streams although most of the codes are identical with just a few different stream-specific function calls. This patch unifies these places, removes the superfluous trivial check and flattens the call paths as a cleanup. Meanwhile, for better readability, some codes (e.g. xfer ioctls or forward/rewind ioctls) are factored out as functions. Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-08-30ALSA: Get rid of card power_lockTakashi Iwai4-74/+53
Currently we're taking power_lock at each card component for assuring the power-up sequence, but it doesn't help anything in the implementation at the moment: it just serializes unnecessarily the callers, but it doesn't protect about the power state change itself. It used to have some usefulness in the early days where we managed the PM manually. But now the suspend/resume core procedure is beyond our hands, and power_lock lost its meaning. This patch drops the power_lock from allover the places. There shouldn't be any issues by this change, as it's no helper regarding the power state change. Rather we'll get better performance by removing the serialization; which is the only slight concern of any behavior change, but it can't be a showstopper, after all. Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-08-30Merge branch 'for-linus' into for-nextTakashi Iwai1-1/+5
2017-08-30ALSA: pcm: Fix power lock unbalance via OSS emulationTakashi Iwai1-1/+5
PCM OSS emulation issues the drain ioctl without power lock. It used to work in the earlier kernels as the power lock was taken inside snd_pcm_drain() itself. But since 68b4acd32249 ("ALSA: pcm: Apply power lock globally to common ioctls"), the power lock is taken outside the function. Due to that change, the call via OSS emulation leads to the unbalanced power lock, thus it deadlocks. As a quick fix, just take the power lock before snd_pcm_drain() call for OSS emulation path. A better cleanup will follow later. Fixes: 68b4acd32249 ("ALSA: pcm: Apply power lock globally to common ioctls") Reported-and-tested-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-08-25ALSA: pcm: Correct broken procfs set upTakashi Iwai1-1/+2
The commit c8da9be4a75f ("ALSA: pcm: Adjust nine function calls together with a variable assignment") contained a badly incorrect conversion, a "status" PCM procfs creation was replaced with the next one. Luckily, this could be spotted easily by the kernel runtime warning. Fixes: c8da9be4a75f ("ALSA: pcm: Adjust nine function calls together...") Reported-by: Fabio Estevam <fabio.estevam@nxp.com> Tested-by: Fabio Estevam <fabio.estevam@nxp.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-08-24ALSA: control: TLV data is unavailable at initial state of user-defined ↵Takashi Sakamoto1-4/+15
element set For user-defined element set, in its initial state, TLV data is not registered. It's firstly available when any application register it by an additional operation. However, in current implementation, it's available in its initial state. As a result, applications get -ENXIO to read it. This commit controls its readability to manage info flags properly. In an initial state, elements don't have SND_CTL_ELEM_ACCESS_TLV_READ flag. Once TLV write operation is executed, they get the flag. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-08-24ALSA: control: queue TLV event for a set of user-defined elementTakashi Sakamoto1-1/+6
In a design of user-defined element set, applications allow to change TLV data on the set. This operation doesn't only affects to a target element, but also to elements in the set. This commit generates TLV event for all of elements in the set when the TLV data is changed. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-08-24ALSA: control: delegate TLV eventing to each driverTakashi Sakamoto1-9/+3
In a design of ALSA control core, a set of elements is represented by 'struct snd_kcontrol' to share common attributes. The set of elements shares TLV (Type-Length-Value) data, too. On the other hand, in ALSA control interface/protocol for applications, a TLV operation is committed to an element. Totally, the operation can have sub-effect to the other elements in the set. For example, TLV_WRITE operation is expected to change TLV data, which returns to applications. Applications attempt to change the TLV data per element, but in the above design, they can effect to elements in the same set. As a default, ALSA control core has no implementation except for TLV_READ operation. Thus, the above design looks to have no issue. However, in kernel APIs of ALSA control component, developers can program a handler for any request of the TLV operation. Therefore, for elements in a set which has the handler, applications can commit TLV_WRITE and TLV_COMMAND requests. For the above scenario, ALSA control core assist notification. When the handler returns positive value, the core queueing an event for a requested element. However, this includes design defects that the event is not queued for the other element in a set. Actually, developers can program the handlers to keep per-element TLV data, but it depends on each driver. As of v4.13-rc6, there's no driver in tree to utilize the notification, except for user-defined element set. This commit delegates the notification into each driver to prevent developers from the design defects. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>