[syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7d0a66e4bb90 Linux 6.18
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=110d0512580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f30cc590c4f6da44
dashboard link: https://syzkaller.appspot.com/bug?extid=641eec6b7af1f62f2b99
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=150d0512580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3e289f3ec7e8/disk-7d0a66e4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bf695f1b8080/vmlinux-7d0a66e4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/eb2f95cf98c6/bzImage-7d0a66e4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com

2025/12/01 16:45:07 executed programs: 5
BUG: memory leak
unreferenced object 0xffff888112d6b200 (size 248):
  comm "syz.0.17", pid 6070, jiffies 4294944719
  hex dump (first 32 bytes):
    40 f8 56 0d 81 88 ff ff 00 00 00 00 00 00 00 00  @.V.............
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc 9dd5d643):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888112e96200 (size 248):
  comm "syz.0.18", pid 6072, jiffies 4294944721
  hex dump (first 32 bytes):
    40 f8 56 0d 81 88 ff ff 00 00 00 00 00 00 00 00  @.V.............
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc 79b7669c):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888112e5ed00 (size 248):
  comm "syz.0.19", pid 6073, jiffies 4294944722
  hex dump (first 32 bytes):
    40 f8 56 0d 81 88 ff ff 00 00 00 00 00 00 00 00  @.V.............
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc 11e3e38b):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888127618400 (size 248):
  comm "syz.0.20", pid 6127, jiffies 4294945384
  hex dump (first 32 bytes):
    40 f8 56 0d 81 88 ff ff 00 00 00 00 00 00 00 00  @.V.............
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc b9653957):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff8881262cf200 (size 248):
  comm "syz.0.21", pid 6128, jiffies 4294945385
  hex dump (first 32 bytes):
    40 f8 56 0d 81 88 ff ff 00 00 00 00 00 00 00 00  @.V.............
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc 457654b1):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

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


---
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 syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

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.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Re: [syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[Jens Axboe]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.18

diff --git a/io_uring/poll.c b/io_uring/poll.c
index b9681d0f9f13..5df09e4e958d 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -922,6 +922,11 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
 		goto out;
 	}
 
+	/*
+	 * Set cancel res early, so io_poll_add() can overwrite it, if
+	 * necessary.
+	 */
+	io_req_set_res(preq, -ECANCELED, 0);
 	if (poll_update->update_events || poll_update->update_user_data) {
 		/* only mask one event flags, keep behavior flags */
 		if (poll_update->update_events) {
@@ -936,12 +941,12 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
 
 		ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED);
 		/* successfully updated, don't complete poll request */
-		if (!ret2 || ret2 == -EIOCBQUEUED)
+		if (ret2 == IOU_ISSUE_SKIP_COMPLETE)
 			goto out;
 	}
 
-	req_set_fail(preq);
-	io_req_set_res(preq, -ECANCELED, 0);
+	if (preq->cqe.res < 0)
+		req_set_fail(preq);
 	preq->io_task_work.func = io_req_task_complete;
 	io_req_task_work_add(preq);
 out:

-- 
Jens Axboe

Re: [syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[shaurya]

[-- Attachment #1: Type: text/plain, Size: 84 bytes --]

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


[-- Attachment #2: 0001-io_uring-fix-memory-leak-by-freeing-cached-requests-.patch --]
[-- Type: text/x-patch, Size: 1632 bytes --]

From c30efa1f5bafdfe1046a29b0c0f3b7f7b41cbea4 Mon Sep 17 00:00:00 2001
From: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
Date: Tue, 2 Dec 2025 01:57:40 +0530
Subject: [PATCH] io_uring: fix memory leak by freeing cached requests before
 percpu_ref exit

In io_ring_ctx_free(), io_req_caches_free() was called after
percpu_ref_exit(). The cached requests need percpu_ref_put_many()
to balance the percpu_ref_get_many() done during allocation in
__io_alloc_req_refill(). If percpu_ref_exit() runs first, those
put operations cannot properly balance the references, leaving
allocated io_kiocb objects unreachable and causing kmemleak to
report them as memory leaks.

Move io_req_caches_free() before percpu_ref_exit() to ensure the
cached requests are freed while the percpu_ref is still valid.

Reported-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug\?extid\=641eec6b7af1f62f2b99
Fixes: 63de899cb622 ("io_uring: count allocated requests")
Cc: stable@vger.kernel.org
Signed-off-by: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
---
 io_uring/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 02339b74ba8d..99ddabb07fbd 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2868,9 +2868,9 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 	if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
 		static_branch_dec(&io_key_has_sqarray);
 
+	io_req_caches_free(ctx);
 	percpu_ref_exit(&ctx->refs);
 	free_uid(ctx->user);
-	io_req_caches_free(ctx);
 
 	WARN_ON_ONCE(ctx->nr_req_allocated);
 
-- 
2.34.1

Re: [syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

SYZFAIL: failed to recv rpc

SYZFAIL: failed to recv rpc
fd=3 want=4 recv=0 n=0 (errno 9: Bad file descriptor)


Warning: Permanently added '10.128.1.13' (ED25519) to the list of known hosts.
2025/12/01 20:59:35 parsed 1 programs
[   45.094356][ T5813] cgroup: Unknown subsys name 'net'
[   45.202443][ T5813] cgroup: Unknown subsys name 'cpuset'
[   45.208862][ T5813] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[   53.863046][ T5813] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[   55.317007][ T5825] soft_limit_in_bytes is deprecated and will be removed. Please report your usecase to linux-mm@kvack.org if you depend on this functionality.
[   55.448849][ T5830] chnl_net:caif_netlink_parms(): no params data found
[   55.468796][ T5830] bridge0: port 1(bridge_slave_0) entered blocking state
[   55.476764][ T5830] bridge0: port 1(bridge_slave_0) entered disabled state
[   55.484104][ T5830] bridge_slave_0: entered allmulticast mode
[   55.490494][ T5830] bridge_slave_0: entered promiscuous mode
[   55.497389][ T5830] bridge0: port 2(bridge_slave_1) entered blocking state
[   55.504651][ T5830] bridge0: port 2(bridge_slave_1) entered disabled state
[   55.511920][ T5830] bridge_slave_1: entered allmulticast mode
[   55.518298][ T5830] bridge_slave_1: entered promiscuous mode
[   55.530562][ T5830] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   55.540621][ T5830] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   55.555225][ T5830] team0: Port device team_slave_0 added
[   55.561419][ T5830] team0: Port device team_slave_1 added
[   55.571641][ T5830] batman_adv: batadv0: Adding interface: batadv_slave_0
[   55.578610][ T5830] batman_adv: batadv0: The MTU of interface batadv_slave_0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
[   55.604931][ T5830] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   55.616342][ T5830] batman_adv: batadv0: Adding interface: batadv_slave_1
[   55.623586][ T5830] batman_adv: batadv0: The MTU of interface batadv_slave_1 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
[   55.649758][ T5830] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   55.667015][ T5830] hsr_slave_0: entered promiscuous mode
[   55.672837][ T5830] hsr_slave_1: entered promiscuous mode
[   55.702718][ T5830] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   55.710523][ T5830] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   55.718180][ T5830] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   55.726058][ T5830] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   55.738320][ T5830] bridge0: port 2(bridge_slave_1) entered blocking state
[   55.745549][ T5830] bridge0: port 2(bridge_slave_1) entered forwarding state
[   55.752892][ T5830] bridge0: port 1(bridge_slave_0) entered blocking state
[   55.759930][ T5830] bridge0: port 1(bridge_slave_0) entered forwarding state
[   55.777110][ T5830] 8021q: adding VLAN 0 to HW filter on device bond0
[   55.786285][   T12] bridge0: port 1(bridge_slave_0) entered disabled state
[   55.793904][   T12] bridge0: port 2(bridge_slave_1) entered disabled state
[   55.803960][ T5830] 8021q: adding VLAN 0 to HW filter on device team0
[   55.812453][   T59] bridge0: port 1(bridge_slave_0) entered blocking state
[   55.819693][   T59] bridge0: port 1(bridge_slave_0) entered forwarding state
[   55.831755][   T59] bridge0: port 2(bridge_slave_1) entered blocking state
[   55.838825][   T59] bridge0: port 2(bridge_slave_1) entered forwarding state
[   55.879152][ T5830] 8021q: adding VLAN 0 to HW filter on device batadv0
[   55.894511][ T5830] veth0_vlan: entered promiscuous mode
[   55.901971][ T5830] veth1_vlan: entered promiscuous mode
[   55.913067][ T5830] veth0_macvtap: entered promiscuous mode
[   55.919675][ T5830] veth1_macvtap: entered promiscuous mode
[   55.928894][ T5830] batman_adv: batadv0: Interface activated: batadv_slave_0
[   55.938300][ T5830] batman_adv: batadv0: Interface activated: batadv_slave_1
[   55.947580][   T12] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   55.956434][   T12] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   55.965897][   T12] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   55.974873][   T12] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   56.025363][   T58] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   56.088083][   T58] netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   56.134632][   T58] netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   56.183062][   T58] netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   56.198760][   T12] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   56.207701][   T12] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   56.218293][   T12] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   56.226287][   T12] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   56.343504][ T5892] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   56.350743][ T5892] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   56.358165][ T5892] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   56.365814][ T5892] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   56.373433][ T5892] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
2025/12/01 20:59:49 executed programs: 0
[   59.121698][   T58] bridge_slave_1: left allmulticast mode
[   59.127497][   T58] bridge_slave_1: left promiscuous mode
[   59.134848][   T58] bridge0: port 2(bridge_slave_1) entered disabled state
[   59.142486][   T58] bridge_slave_0: left allmulticast mode
[   59.148220][   T58] bridge_slave_0: left promiscuous mode
[   59.154181][   T58] bridge0: port 1(bridge_slave_0) entered disabled state
[   59.203736][   T58] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[   59.213014][   T58] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[   59.222011][   T58] bond0 (unregistering): Released all slaves
[   59.313631][   T58] hsr_slave_0: left promiscuous mode
[   59.319216][   T58] hsr_slave_1: left promiscuous mode
[   59.324844][   T58] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[   59.332334][   T58] batman_adv: batadv0: Removing interface: batadv_slave_0
[   59.339764][   T58] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[   59.347198][   T58] batman_adv: batadv0: Removing interface: batadv_slave_1
[   59.355640][   T58] veth1_macvtap: left promiscuous mode
[   59.361130][   T58] veth0_macvtap: left promiscuous mode
[   59.366742][   T58] veth1_vlan: left promiscuous mode
[   59.372040][   T58] veth0_vlan: left promiscuous mode
[   59.399875][   T58] team0 (unregistering): Port device team_slave_1 removed
[   59.408653][   T58] team0 (unregistering): Port device team_slave_0 removed
[   62.564840][ T5134] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   62.572035][ T5134] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   62.579170][ T5134] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   62.586644][ T5134] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   62.594085][ T5134] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   62.632210][ T5983] chnl_net:caif_netlink_parms(): no params data found
[   62.651514][ T5983] bridge0: port 1(bridge_slave_0) entered blocking state
[   62.658706][ T5983] bridge0: port 1(bridge_slave_0) entered disabled state
[   62.666137][ T5983] bridge_slave_0: entered allmulticast mode
[   62.672389][ T5983] bridge_slave_0: entered promiscuous mode
[   62.678796][ T5983] bridge0: port 2(bridge_slave_1) entered blocking state
[   62.686192][ T5983] bridge0: port 2(bridge_slave_1) entered disabled state
[   62.693313][ T5983] bridge_slave_1: entered allmulticast mode
[   62.699554][ T5983] bridge_slave_1: entered promiscuous mode
[   62.711639][ T5983] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   62.721580][ T5983] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   62.735611][ T5983] team0: Port device team_slave_0 added
[   62.742046][ T5983] team0: Port device team_slave_1 added
[   62.752167][ T5983] batman_adv: batadv0: Adding interface: batadv_slave_0
[   62.759107][ T5983] batman_adv: batadv0: The MTU of interface batadv_slave_0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
[   62.785244][ T5983] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   62.796357][ T5983] batman_adv: batadv0: Adding interface: batadv_slave_1
[   62.803353][ T5983] batman_adv: batadv0: The MTU of interface batadv_slave_1 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
[   62.829487][ T5983] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   62.847117][ T5983] hsr_slave_0: entered promiscuous mode
[   62.852936][ T5983] hsr_slave_1: entered promiscuous mode
[   63.036253][ T5983] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   63.045375][ T5983] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   63.053519][ T5983] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   63.061789][ T5983] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   63.075975][ T5983] bridge0: port 2(bridge_slave_1) entered blocking state
[   63.083083][ T5983] bridge0: port 2(bridge_slave_1) entered forwarding state
[   63.090673][ T5983] bridge0: port 1(bridge_slave_0) entered blocking state
[   63.097877][ T5983] bridge0: port 1(bridge_slave_0) entered forwarding state
[   63.122294][ T5983] 8021q: adding VLAN 0 to HW filter on device bond0
[   63.132914][   T58] bridge0: port 1(bridge_slave_0) entered disabled state
[   63.140548][   T58] bridge0: port 2(bridge_slave_1) entered disabled state
[   63.152272][ T5983] 8021q: adding VLAN 0 to HW filter on device team0
[   63.162216][   T79] bridge0: port 1(bridge_slave_0) entered blocking state
[   63.169296][   T79] bridge0: port 1(bridge_slave_0) entered forwarding state
[   63.178607][   T58] bridge0: port 2(bridge_slave_1) entered blocking state
[   63.185727][   T58] bridge0: port 2(bridge_slave_1) entered forwarding state
[   63.247759][ T5983] 8021q: adding VLAN 0 to HW filter on device batadv0
[   63.268232][ T5983] veth0_vlan: entered promiscuous mode
[   63.276325][ T5983] veth1_vlan: entered promiscuous mode
[   63.296850][ T5983] veth0_macvtap: entered promiscuous mode
[   63.304290][ T5983] veth1_macvtap: entered promiscuous mode
[   63.314925][ T5983] batman_adv: batadv0: Interface activated: batadv_slave_0
[   63.334416][ T5983] batman_adv: batadv0: Interface activated: batadv_slave_1
[   63.344953][   T12] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   63.354046][   T79] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   63.363838][   T79] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   63.383838][   T79] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
SYZFAIL: failed to recv rpc
fd=3 want=4 recv=0 n=0 (errno 9: Bad file descriptor)
[   63.428886][   T79] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   63.440292][   T79] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   63.451963][   T12] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   63.463029][   T12] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1359059719=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs-2/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs-2/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs-2/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.4'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at d6526ea3e
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=d6526ea3e6ad9081c902859bbb80f9f840377cb4 -X github.com/google/syzkaller/prog.gitRevisionDate=20251126-113115"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=d6526ea3e6ad9081c902859bbb80f9f840377cb4 -X github.com/google/syzkaller/prog.gitRevisionDate=20251126-113115"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=d6526ea3e6ad9081c902859bbb80f9f840377cb4 -X github.com/google/syzkaller/prog.gitRevisionDate=20251126-113115"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"d6526ea3e6ad9081c902859bbb80f9f840377cb4\"
/usr/bin/ld: /tmp/ccZ4MFua.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x104): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null



Tested on:

commit:         7d0a66e4 Linux 6.18
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.18
kernel config:  https://syzkaller.appspot.com/x/.config?x=f30cc590c4f6da44
dashboard link: https://syzkaller.appspot.com/bug?extid=641eec6b7af1f62f2b99
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13688512580000

Re: [syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
memory leak in io_submit_sqes

2025/12/01 21:23:33 executed programs: 5
BUG: memory leak
unreferenced object 0xffff888111254200 (size 248):
  comm "syz.0.17", pid 6735, jiffies 4294946584
  hex dump (first 32 bytes):
    c0 e9 e3 09 81 88 ff ff 00 00 00 00 00 00 00 00  ................
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc 2fa747c9):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888111262200 (size 248):
  comm "syz.0.18", pid 6740, jiffies 4294946586
  hex dump (first 32 bytes):
    c0 e9 e3 09 81 88 ff ff 00 00 00 00 00 00 00 00  ................
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc 95820259):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888125155300 (size 248):
  comm "syz.0.19", pid 6744, jiffies 4294946588
  hex dump (first 32 bytes):
    c0 e9 e3 09 81 88 ff ff 00 00 00 00 00 00 00 00  ................
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc 7f690aa4):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888122d56200 (size 248):
  comm "syz.0.20", pid 6764, jiffies 4294947184
  hex dump (first 32 bytes):
    c0 e9 e3 09 81 88 ff ff 00 00 00 00 00 00 00 00  ................
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc 1e329da4):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888126b78d00 (size 248):
  comm "syz.0.21", pid 6766, jiffies 4294947184
  hex dump (first 32 bytes):
    c0 e9 e3 09 81 88 ff ff 00 00 00 00 00 00 00 00  ................
    3c 20 00 c0 00 00 00 00 00 00 00 00 00 00 00 00  < ..............
  backtrace (crc d8b7eea):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4983 [inline]
    kmem_cache_alloc_bulk_noprof+0x220/0x3e0 mm/slub.c:7497
    __io_alloc_req_refill+0x54/0x1a0 io_uring/io_uring.c:1058
    io_alloc_req io_uring/io_uring.h:543 [inline]
    io_submit_sqes+0x584/0xe80 io_uring/io_uring.c:2438
    __do_sys_io_uring_enter+0x83f/0xcf0 io_uring/io_uring.c:3516
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xfa0 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

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


Tested on:

commit:         7d0a66e4 Linux 6.18
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=131aa512580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f30cc590c4f6da44
dashboard link: https://syzkaller.appspot.com/bug?extid=641eec6b7af1f62f2b99
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14448512580000

Re: [syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[Jens Axboe]

On 12/1/25 2:24 PM, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> memory leak in io_submit_sqes

Yep that patch made no sense to me...

Shaurya Rane, was that some kind of AI hallucination, or what led to that?!

-- 
Jens Axboe

Re: [syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[Jens Axboe]

Let's try this again, seemed like a testing failure last time...

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

diff --git a/io_uring/poll.c b/io_uring/poll.c
index b9681d0f9f13..0d5bb90d4743 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -936,12 +936,17 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
 
 		ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED);
 		/* successfully updated, don't complete poll request */
-		if (!ret2 || ret2 == -EIOCBQUEUED)
+		if (ret2 == IOU_ISSUE_SKIP_COMPLETE)
 			goto out;
+		/* request completed as part of the update, complete it */
+		else if (ret2 == IOU_COMPLETE)
+			goto complete;
 	}
 
-	req_set_fail(preq);
 	io_req_set_res(preq, -ECANCELED, 0);
+complete:
+	if (preq->cqe.res < 0)
+		req_set_fail(preq);
 	preq->io_task_work.func = io_req_task_complete;
 	io_req_task_work_add(preq);
 out:

-- 
Jens Axboe

Re: [syzbot] [io-uring?] memory leak in io_submit_sqes (5)

[syzbot]

Hello,

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

Reported-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com
Tested-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com

Tested on:

commit:         7d0a66e4 Linux 6.18
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11128512580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f30cc590c4f6da44
dashboard link: https://syzkaller.appspot.com/bug?extid=641eec6b7af1f62f2b99
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=13d09112580000

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