[syzbot] [usb?] memory leak in f_uac2_opts_p_srate_store

[syzbot] [usb?] memory leak in f_uac2_opts_p_srate_store

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    fc02acf6ac0c Merge tag 'platform-drivers-x86-v7.2-4' of gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11b3a49e580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ba7c2d1679fb08a2
dashboard link: https://syzkaller.appspot.com/bug?extid=87c10526d2cfa8d14ff6
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=148cd1b9580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=141f38c6580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b9d1b7c8f45c/disk-fc02acf6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a68eafefb074/vmlinux-fc02acf6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/89c624fcb62b/bzImage-fc02acf6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+87c10526d2cfa8d14ff6@syzkaller.appspotmail.com

2026/07/29 19:24:36 executed programs: 7
BUG: memory leak
unreferenced object 0xffff888112f1fd80 (size 64):
  comm "syz.0.21", pid 5964, jiffies 4294942888
  hex dump (first 32 bytes):
    34 34 31 30 30 00 34 38 30 30 30 00 38 38 32 30  44100.48000.8820
    30 00 39 36 30 30 30 00 31 37 36 34 30 30 00 31  0.96000.176400.1
  backtrace (crc 6cdecf20):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4597 [inline]
    slab_alloc_node mm/slub.c:4917 [inline]
    __do_kmalloc_node mm/slub.c:5333 [inline]
    __kmalloc_node_track_caller_noprof+0x3d3/0x570 mm/slub.c:5471
    __kmemdup_nul mm/util.c:64 [inline]
    kstrdup+0x3c/0x80 mm/util.c:84
    f_uac2_opts_p_srate_store+0xbb/0x170 drivers/usb/gadget/function/f_uac2.c:2087
    flush_write_buffer fs/configfs/file.c:207 [inline]
    configfs_write_iter+0x10d/0x1a0 fs/configfs/file.c:229
    new_sync_write fs/read_write.c:595 [inline]
    vfs_write+0x3ac/0x720 fs/read_write.c:687
    ksys_write+0xa5/0x170 fs/read_write.c:739
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xf8/0x610 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888113454dc0 (size 64):
  comm "syz.0.23", pid 5967, jiffies 4294943452
  hex dump (first 32 bytes):
    34 34 31 30 30 00 34 38 30 30 30 00 38 38 32 30  44100.48000.8820
    30 00 39 36 30 30 30 00 31 37 36 34 30 30 00 31  0.96000.176400.1
  backtrace (crc 6cdecf20):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4597 [inline]
    slab_alloc_node mm/slub.c:4917 [inline]
    __do_kmalloc_node mm/slub.c:5333 [inline]
    __kmalloc_node_track_caller_noprof+0x3d3/0x570 mm/slub.c:5471
    __kmemdup_nul mm/util.c:64 [inline]
    kstrdup+0x3c/0x80 mm/util.c:84
    f_uac2_opts_p_srate_store+0xbb/0x170 drivers/usb/gadget/function/f_uac2.c:2087
    flush_write_buffer fs/configfs/file.c:207 [inline]
    configfs_write_iter+0x10d/0x1a0 fs/configfs/file.c:229
    new_sync_write fs/read_write.c:595 [inline]
    vfs_write+0x3ac/0x720 fs/read_write.c:687
    ksys_write+0xa5/0x170 fs/read_write.c:739
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xf8/0x610 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

connection error: failed to recv *flatrpc.ExecutorMessageRawT: EOF


---
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Forwarded: [PATCH] usb: gadget: f_uac2: Fix memory leak in srate parsing

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: [PATCH] usb: gadget: f_uac2: Fix memory leak in srate parsing
Author: ryan.mehri1@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fc02acf6ac0c

Signed-off-by: Ryan Mehri <ryan.mehri1@gmail.com>
---
 drivers/usb/gadget/function/f_uac2.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index 897787d0803c..5d6701019e10 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -2013,6 +2013,7 @@ static ssize_t f_uac2_opts_##name##_store(struct config_item *item,	\
 {									\
 	struct f_uac2_opts *opts = to_f_uac2_opts(item);		\
 	char *split_page = NULL;					\
+	char *p = NULL;							\
 	int ret = -EINVAL;						\
 	char *token;							\
 	u32 num;							\
@@ -2026,8 +2027,8 @@ static ssize_t f_uac2_opts_##name##_store(struct config_item *item,	\
 									\
 	i = 0;								\
 	memset(opts->name##s, 0x00, sizeof(opts->name##s));		\
-	split_page = kstrdup(page, GFP_KERNEL);				\
-	while ((token = strsep(&split_page, ",")) != NULL) {		\
+	split_page = p = kstrdup(page, GFP_KERNEL);			\
+	while ((token = strsep(&p, ",")) != NULL) {			\
 		ret = kstrtou32(token, 0, &num);			\
 		if (ret)						\
 			goto end;					\
-- 
2.55.0

Re: [syzbot] [usb?] memory leak in f_uac2_opts_p_srate_store

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+87c10526d2cfa8d14ff6@syzkaller.appspotmail.com
Tested-by: syzbot+87c10526d2cfa8d14ff6@syzkaller.appspotmail.com

Tested on:

commit:         fc02acf6 Merge tag 'platform-drivers-x86-v7.2-4' of gi..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11e6bdb9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ba7c2d1679fb08a2
dashboard link: https://syzkaller.appspot.com/bug?extid=87c10526d2cfa8d14ff6
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16285e32580000

Note: testing is done by a robot and is best-effort only.