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authorTakashi Iwai <tiwai@suse.de>2022-07-28 14:59:42 +0200
committerTakashi Iwai <tiwai@suse.de>2022-07-29 12:57:10 +0200
commitef34a0ae7a2654bc9e58675e36898217fb2799d8 (patch)
tree3444d3d9264ced511f8378bf656b276fe800cc97 /include/sound/core.h
parent87eb04bb87fbdf1d53f0fc64e6fc56ba2b504762 (diff)
downloadlinux-ef34a0ae7a2654bc9e58675e36898217fb2799d8.tar.bz2
ALSA: core: Add async signal helpers
Currently the call of kill_fasync() from an interrupt handler might lead to potential spin deadlocks, as spotted by syzkaller. Unfortunately, it's not so trivial to fix this lock chain as it's involved with the tasklist_lock that is touched in allover places. As a temporary workaround, this patch provides the way to defer the async signal notification in a work. The new helper functions, snd_fasync_helper() and snd_kill_faync() are replacements for fasync_helper() and kill_fasync(), respectively. In addition, snd_fasync_free() needs to be called at the destructor of the relevant file object. Link: https://lore.kernel.org/r/20220728125945.29533-2-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include/sound/core.h')
-rw-r--r--include/sound/core.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/sound/core.h b/include/sound/core.h
index dd28de2343b8..4365c35d038b 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -507,4 +507,12 @@ snd_pci_quirk_lookup_id(u16 vendor, u16 device,
}
#endif
+/* async signal helpers */
+struct snd_fasync;
+
+int snd_fasync_helper(int fd, struct file *file, int on,
+ struct snd_fasync **fasyncp);
+void snd_kill_fasync(struct snd_fasync *fasync, int signal, int poll);
+void snd_fasync_free(struct snd_fasync *fasync);
+
#endif /* __SOUND_CORE_H */