* [syzbot] [usb?] memory leak in f_uac2_opts_c_srate_store
@ 2026-07-31 0:11 syzbot
2026-08-02 0:04 ` Forwarded: #syz test syzbot
0 siblings, 1 reply; 3+ messages in thread
From: syzbot @ 2026-07-31 0:11 UTC (permalink / raw)
To: gregkh, linux-kernel, linux-usb, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 3dab139d4795 Merge tag 'rust-fixes-7.2-2' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16e611b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ba7c2d1679fb08a2
dashboard link: https://syzkaller.appspot.com/bug?extid=ebd045a6645cfb713c95
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=166ba499580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11e611b9580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8c49d395f8d0/disk-3dab139d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/deff2ace5e6a/vmlinux-3dab139d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2c90a783f940/bzImage-3dab139d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ebd045a6645cfb713c95@syzkaller.appspotmail.com
2026/07/26 16:23:20 executed programs: 5
BUG: memory leak
unreferenced object 0xffff888112a01e00 (size 64):
comm "syz.0.17", pid 5945, jiffies 4294942115
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 9bbd8bc9):
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_c_srate_store+0xbb/0x170 drivers/usb/gadget/function/f_uac2.c:2091
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 0xffff8881128d2d80 (size 64):
comm "syz.0.18", pid 5946, jiffies 4294942116
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 9bbd8bc9):
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_c_srate_store+0xbb/0x170 drivers/usb/gadget/function/f_uac2.c:2091
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 0xffff88811193ee80 (size 64):
comm "syz.0.21", pid 5964, jiffies 4294942644
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 9bbd8bc9):
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_c_srate_store+0xbb/0x170 drivers/usb/gadget/function/f_uac2.c:2091
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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^ permalink raw reply [flat|nested] 3+ messages in thread* Forwarded: #syz test
2026-07-31 0:11 [syzbot] [usb?] memory leak in f_uac2_opts_c_srate_store syzbot
@ 2026-08-02 0:04 ` syzbot
0 siblings, 0 replies; 3+ messages in thread
From: syzbot @ 2026-08-02 0:04 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.
***
Subject: #syz test
Author: rwarwatkar@gmail.com
From 89443f65c32564e688448a39ba54cd13a1f8ef67 Mon Sep 17 00:00:00 2001
From: Rituparna Warwatkar <rwarwatkar@gmail.com>
Date: Sat, 1 Aug 2026 23:38:07 +0000
Subject: [PATCH] usb: gadget: f_uac2: fix memory leak in sample rate store
f_uac2_opts_{p,c}_srate_store() duplicate the input page with kstrdup()
and then tokenize it with strsep(&split_page, ","). strsep() advances
the pointer it is given, so by the time the parsing loop finishes
split_page points at the end of the string (or NULL). The subsequent
kfree(split_page) therefore frees the wrong pointer (NULL when the
whole buffer was consumed), leaking the buffer allocated by kstrdup():
BUG: memory leak
unreferenced object 0xffff888112a01e00 (size 64):
kstrdup
f_uac2_opts_c_srate_store
configfs_write_iter
vfs_write
ksys_write
Keep the original allocation in split_page and hand a separate iterator
to strsep(), so the buffer is always freed. While at it, handle a
kstrdup() failure instead of dereferencing NULL. Both the p_srate and
c_srate attributes use the same macro and are fixed together.
Fixes: a7339e4f5788 ("usb: gadget: f_uac2: Support multiple sampling rates")
Reported-by: syzbot+ebd045a6645cfb713c95@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=ebd045a6645cfb713c95
Signed-off-by: Rituparna Warwatkar <rwarwatkar@gmail.com>
---
drivers/usb/gadget/function/f_uac2.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index 897787d0803..8facf289710 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 *rest; \
int ret = -EINVAL; \
char *token; \
u32 num; \
@@ -2027,7 +2028,12 @@ 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) { \
+ if (!split_page) { \
+ ret = -ENOMEM; \
+ goto end; \
+ } \
+ rest = split_page; \
+ while ((token = strsep(&rest, ",")) != NULL) { \
ret = kstrtou32(token, 0, &num); \
if (ret) \
goto end; \
--
2.47.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
[parent not found: <20260802000350.90671-1-rituu@riacini.speedport.ip>]
end of thread, other threads:[~2026-08-02 0:34 UTC | newest]
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2026-07-31 0:11 [syzbot] [usb?] memory leak in f_uac2_opts_c_srate_store syzbot
2026-08-02 0:04 ` Forwarded: #syz test syzbot
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2026-08-02 0:34 ` [syzbot] [usb?] memory leak in f_uac2_opts_c_srate_store syzbot
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