[syzbot] memory leak in binder_transaction (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 59d0d52c30d4 AMerge tag 'netfs-fixes-20221115' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14a7b445880000
kernel config: https://syzkaller.appspot.com/x/.config?x=435fb8cdd395f932
dashboard link: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=114a3b35880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/854c98a663e0/disk-59d0d52c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/233c8e05ab54/vmlinux-59d0d52c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7254f9286f1d/bzImage-59d0d52c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7f10c1...@syzkaller.appspotmail.com

BUG: memory leak
unreferenced object 0xffff88811b0bbe00 (size 32):
comm "syz-executor.1", pid 4041, jiffies 4294986632 (age 15.340s)
hex dump (first 32 bytes):
00 be 0b 1b 81 88 ff ff 00 be 0b 1b 81 88 ff ff ................
03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff814ed530>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1045
[<ffffffff8396b973>] kmalloc include/linux/slab.h:553 [inline]
[<ffffffff8396b973>] kzalloc include/linux/slab.h:689 [inline]
[<ffffffff8396b973>] binder_transaction+0xc53/0x3f20 drivers/android/binder.c:3128
[<ffffffff8396f213>] binder_thread_write+0x5d3/0x1790 drivers/android/binder.c:3975
[<ffffffff839726cb>] binder_ioctl_write_read drivers/android/binder.c:5034 [inline]
[<ffffffff839726cb>] binder_ioctl+0x22fb/0x3a30 drivers/android/binder.c:5321
[<ffffffff8161f20c>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff8161f20c>] __do_sys_ioctl fs/ioctl.c:870 [inline]
[<ffffffff8161f20c>] __se_sys_ioctl fs/ioctl.c:856 [inline]
[<ffffffff8161f20c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
[<ffffffff848802d5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff848802d5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84a00087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd



---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Hillf Danton]

On 20 Nov 2022 13:51:41 -0800

> syzbot found the following issue on:
>
> HEAD commit: 59d0d52c30d4 AMerge tag 'netfs-fixes-20221115' of git://gi..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14a7b445880000
> kernel config: https://syzkaller.appspot.com/x/.config?x=435fb8cdd395f932
> dashboard link: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=114a3b35880000

Add debug info for BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 59d0d52c30d4

--- x/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -4774,6 +4774,7 @@ static void binder_release_work(struct b
"undelivered TRANSACTION_ERROR: %u\n",
e->cmd);
} break;
+ case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT:
case BINDER_WORK_TRANSACTION_COMPLETE: {
binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
"undelivered TRANSACTION_COMPLETE\n");
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
no output from test machine



Tested on:

commit: 59d0d52c AMerge tag 'netfs-fixes-20221115' of git://gi..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1759f9f9880000

kernel config: https://syzkaller.appspot.com/x/.config?x=435fb8cdd395f932
dashboard link: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=17dd366e880000

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 0bb80ecc33a8 Linux 6.6-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=177ee3c8680000
kernel config: https://syzkaller.appspot.com/x/.config?x=99ce3535087fc27
dashboard link: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=107b832c680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=147332b4680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ce21ae500663/disk-0bb80ecc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1d2f34908198/vmlinux-0bb80ecc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9c6f5eecda20/bzImage-0bb80ecc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7f10c1...@syzkaller.appspotmail.com

BUG: memory leak

unreferenced object 0xffff88810e2d6de0 (size 32):
comm "syz-executor338", pid 5046, jiffies 4294968230 (age 13.590s)

hex dump (first 32 bytes):

e0 6d 2d 0e 81 88 ff ff e0 6d 2d 0e 81 88 ff ff .m-......m-.....
04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff81573b75>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1114
[<ffffffff83d41873>] kmalloc include/linux/slab.h:599 [inline]
[<ffffffff83d41873>] kzalloc include/linux/slab.h:720 [inline]
[<ffffffff83d41873>] binder_transaction+0x573/0x4050 drivers/android/binder.c:3152
[<ffffffff83d45a05>] binder_thread_write+0x6b5/0x1860 drivers/android/binder.c:4010
[<ffffffff83d486dc>] binder_ioctl_write_read drivers/android/binder.c:5066 [inline]
[<ffffffff83d486dc>] binder_ioctl+0x1b2c/0x3cf0 drivers/android/binder.c:5352
[<ffffffff816b25f2>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff816b25f2>] __do_sys_ioctl fs/ioctl.c:871 [inline]
[<ffffffff816b25f2>] __se_sys_ioctl fs/ioctl.c:857 [inline]
[<ffffffff816b25f2>] __x64_sys_ioctl+0xf2/0x140 fs/ioctl.c:857
[<ffffffff84b30008>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84b30008>] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
[<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[Carlos Llamas]

A transaction complete work is allocated and queued for each
transaction. Under certain conditions the work->type might be marked as
BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT to notify userspace about
potential spamming threads.

However, this work->type is not being handled in binder_release_work()
so it will leak during a clean up. This was reported by syzkaller with
the following kmemleak dump:

BUG: memory leak

unreferenced object 0xffff88810e2d6de0 (size 32):
comm "syz-executor338", pid 5046, jiffies 4294968230 (age 13.590s)

hex dump (first 32 bytes):

e0 6d 2d 0e 81 88 ff ff e0 6d 2d 0e 81 88 ff ff .m-......m-.....

04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:

[<ffffffff81573b75>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1114
[<ffffffff83d41873>] kmalloc include/linux/slab.h:599 [inline]
[<ffffffff83d41873>] kzalloc include/linux/slab.h:720 [inline]
[<ffffffff83d41873>] binder_transaction+0x573/0x4050 drivers/android/binder.c:3152
[<ffffffff83d45a05>] binder_thread_write+0x6b5/0x1860 drivers/android/binder.c:4010
[<ffffffff83d486dc>] binder_ioctl_write_read drivers/android/binder.c:5066 [inline]
[<ffffffff83d486dc>] binder_ioctl+0x1b2c/0x3cf0 drivers/android/binder.c:5352
[<ffffffff816b25f2>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff816b25f2>] __do_sys_ioctl fs/ioctl.c:871 [inline]
[<ffffffff816b25f2>] __se_sys_ioctl fs/ioctl.c:857 [inline]
[<ffffffff816b25f2>] __x64_sys_ioctl+0xf2/0x140 fs/ioctl.c:857
[<ffffffff84b30008>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84b30008>] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
[<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fix the leak by kfreeing this work in binder_release_work().

Cc: sta...@vger.kernel.org
Fixes: a7dc1e6f99df ("binder: tell userspace to dump current backtrace when detected oneway spamming")
Reported-by: syzbot+7f10c1...@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e
Signed-off-by: Carlos Llamas <cmll...@google.com>
---
drivers/android/binder.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 367afac5f1bf..d7aa561f4ef2 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -4831,6 +4831,9 @@ static void binder_release_work(struct binder_proc *proc,
} break;
case BINDER_WORK_NODE:
break;
+ case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT:
+ kfree(w);
+ break;
default:
pr_err("unexpected work type, %d, not freed\n",
wtype);
--
2.42.0.515.g380fc7ccd1-goog

[Carlos Llamas]

A transaction complete work is allocated and queued for each
transaction. Under certain conditions the work->type might be marked as
BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT to notify userspace about

potential spamming threads or as BINDER_WORK_TRANSACTION_PENDING when
the target is currently frozen.

However, these work types are not being handled in binder_release_work()
so they will leak during a cleanup. This was reported by syzkaller with

the following kmemleak dump:

BUG: memory leak
unreferenced object 0xffff88810e2d6de0 (size 32):
comm "syz-executor338", pid 5046, jiffies 4294968230 (age 13.590s)
hex dump (first 32 bytes):
e0 6d 2d 0e 81 88 ff ff e0 6d 2d 0e 81 88 ff ff .m-......m-.....
04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff81573b75>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1114
[<ffffffff83d41873>] kmalloc include/linux/slab.h:599 [inline]
[<ffffffff83d41873>] kzalloc include/linux/slab.h:720 [inline]
[<ffffffff83d41873>] binder_transaction+0x573/0x4050 drivers/android/binder.c:3152
[<ffffffff83d45a05>] binder_thread_write+0x6b5/0x1860 drivers/android/binder.c:4010
[<ffffffff83d486dc>] binder_ioctl_write_read drivers/android/binder.c:5066 [inline]
[<ffffffff83d486dc>] binder_ioctl+0x1b2c/0x3cf0 drivers/android/binder.c:5352
[<ffffffff816b25f2>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff816b25f2>] __do_sys_ioctl fs/ioctl.c:871 [inline]
[<ffffffff816b25f2>] __se_sys_ioctl fs/ioctl.c:857 [inline]
[<ffffffff816b25f2>] __x64_sys_ioctl+0xf2/0x140 fs/ioctl.c:857
[<ffffffff84b30008>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84b30008>] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
[<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fix the leaks by kfreeing these work types in binder_release_work() and
handle them as a BINDER_WORK_TRANSACTION_COMPLETE cleanup.

Cc: sta...@vger.kernel.org
Fixes: 0567461a7a6e ("binder: return pending info for frozen async txns")

Fixes: a7dc1e6f99df ("binder: tell userspace to dump current backtrace when detected oneway spamming")
Reported-by: syzbot+7f10c1...@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e

Suggested-by: Alice Ryhl <alic...@google.com>

Signed-off-by: Carlos Llamas <cmll...@google.com>
---

v2 - Handle also peding work and merge with transaction complete as
suggested by Alice Ryhl. Add corresponding new tags.
v1 - https://lore.kernel.org/all/20230922044241.3...@google.com/
---
drivers/android/binder.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 367afac5f1bf..92128aae2d06 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -4812,6 +4812,8 @@ static void binder_release_work(struct binder_proc *proc,

"undelivered TRANSACTION_ERROR: %u\n",
e->cmd);
} break;

+ case BINDER_WORK_TRANSACTION_PENDING:

+ case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT:
case BINDER_WORK_TRANSACTION_COMPLETE: {
binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
"undelivered TRANSACTION_COMPLETE\n");
--

2.42.0.515.g380fc7ccd1-goog

[Todd Kjos]

On Fri, Sep 22, 2023 at 11:51 AM Alice Ryhl <alic...@google.com> wrote:

> Reviewed-by: Alice Ryhl <alic...@google.com>

Acked-by: Todd Kjos <tk...@google.com>

[Alice Ryhl]

On Fri, Sep 22, 2023 at 7:51 PM Carlos Llamas <cmll...@google.com> wrote:
>

Reviewed-by: Alice Ryhl <alic...@google.com>