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* memory leak in ppp_write
@ 2019-08-05 12:38 syzbot
  2019-08-29 15:32 ` syzbot
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2019-08-05 12:38 UTC (permalink / raw)
  To: ast, bpf, daniel, davem, kafai, linux-kernel, linux-ppp, netdev,
	paulus, songliubraving, syzkaller-bugs, yhs

Hello,

syzbot found the following crash on:

HEAD commit:    d8778f13 Merge tag 'xtensa-20190803' of git://github.com/j..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17a953d6600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=30cef20daf3e9977
dashboard link: https://syzkaller.appspot.com/bug?extid=d9c8bf24e56416d7ce2c
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16da002c600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d9c8bf24e56416d7ce2c@syzkaller.appspotmail.com

2019/08/04 10:45:32 executed programs: 5
2019/08/04 10:45:38 executed programs: 7
2019/08/04 10:45:44 executed programs: 9
2019/08/04 10:45:51 executed programs: 11
BUG: memory leak
unreferenced object 0xffff88811b943200 (size 224):
   comm "syz-executor.0", pid 7102, jiffies 4294951426 (age 8.020s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   backtrace:
     [<00000000612bb18c>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<00000000612bb18c>] slab_post_alloc_hook mm/slab.h:522 [inline]
     [<00000000612bb18c>] slab_alloc_node mm/slab.c:3262 [inline]
     [<00000000612bb18c>] kmem_cache_alloc_node+0x163/0x2f0 mm/slab.c:3574
     [<00000000f510d7dd>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:197
     [<0000000064f35f9b>] alloc_skb include/linux/skbuff.h:1055 [inline]
     [<0000000064f35f9b>] ppp_write+0x48/0x120  
drivers/net/ppp/ppp_generic.c:502
     [<000000007d5732a9>] __vfs_write+0x43/0xa0 fs/read_write.c:494
     [<00000000b490138e>] vfs_write fs/read_write.c:558 [inline]
     [<00000000b490138e>] vfs_write+0xee/0x210 fs/read_write.c:542
     [<00000000d20d33e5>] ksys_write+0x7c/0x130 fs/read_write.c:611
     [<000000007b61e45c>] __do_sys_write fs/read_write.c:623 [inline]
     [<000000007b61e45c>] __se_sys_write fs/read_write.c:620 [inline]
     [<000000007b61e45c>] __x64_sys_write+0x1e/0x30 fs/read_write.c:620
     [<0000000067600a9b>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:296
     [<000000007e48b83c>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



---
This bug 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 bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: memory leak in ppp_write
  2019-08-05 12:38 memory leak in ppp_write syzbot
@ 2019-08-29 15:32 ` syzbot
  2019-09-12 13:34   ` Takeshi Misawa
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2019-08-29 15:32 UTC (permalink / raw)
  To: ast, bpf, daniel, davem, kafai, linux-kernel, linux-ppp, netdev,
	paulus, songliubraving, syzkaller-bugs, yhs

syzbot has found a reproducer for the following crash on:

HEAD commit:    6525771f Merge tag 'arc-5.3-rc7' of git://git.kernel.org/p..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16dc12a2600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6131eafb9408877
dashboard link: https://syzkaller.appspot.com/bug?extid=d9c8bf24e56416d7ce2c
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=116942de600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1179c582600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d9c8bf24e56416d7ce2c@syzkaller.appspotmail.com

executing program
executing program
executing program
executing program
BUG: memory leak
unreferenced object 0xffff88812a17bc00 (size 224):
   comm "syz-executor673", pid 6952, jiffies 4294942888 (age 13.040s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   backtrace:
     [<00000000d110fff9>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<00000000d110fff9>] slab_post_alloc_hook mm/slab.h:522 [inline]
     [<00000000d110fff9>] slab_alloc_node mm/slab.c:3262 [inline]
     [<00000000d110fff9>] kmem_cache_alloc_node+0x163/0x2f0 mm/slab.c:3574
     [<000000002d616113>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:197
     [<000000000167fc45>] alloc_skb include/linux/skbuff.h:1055 [inline]
     [<000000000167fc45>] ppp_write+0x48/0x120  
drivers/net/ppp/ppp_generic.c:502
     [<000000009ab42c0b>] __vfs_write+0x43/0xa0 fs/read_write.c:494
     [<00000000086b2e22>] vfs_write fs/read_write.c:558 [inline]
     [<00000000086b2e22>] vfs_write+0xee/0x210 fs/read_write.c:542
     [<00000000a2b70ef9>] ksys_write+0x7c/0x130 fs/read_write.c:611
     [<00000000ce5e0fdd>] __do_sys_write fs/read_write.c:623 [inline]
     [<00000000ce5e0fdd>] __se_sys_write fs/read_write.c:620 [inline]
     [<00000000ce5e0fdd>] __x64_sys_write+0x1e/0x30 fs/read_write.c:620
     [<00000000d9d7b370>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:296
     [<0000000006e6d506>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff888121203900 (size 224):
   comm "syz-executor673", pid 6965, jiffies 4294943430 (age 7.620s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   backtrace:
     [<00000000d110fff9>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<00000000d110fff9>] slab_post_alloc_hook mm/slab.h:522 [inline]
     [<00000000d110fff9>] slab_alloc_node mm/slab.c:3262 [inline]
     [<00000000d110fff9>] kmem_cache_alloc_node+0x163/0x2f0 mm/slab.c:3574
     [<000000002d616113>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:197
     [<000000000167fc45>] alloc_skb include/linux/skbuff.h:1055 [inline]
     [<000000000167fc45>] ppp_write+0x48/0x120  
drivers/net/ppp/ppp_generic.c:502
     [<000000009ab42c0b>] __vfs_write+0x43/0xa0 fs/read_write.c:494
     [<00000000086b2e22>] vfs_write fs/read_write.c:558 [inline]
     [<00000000086b2e22>] vfs_write+0xee/0x210 fs/read_write.c:542
     [<00000000a2b70ef9>] ksys_write+0x7c/0x130 fs/read_write.c:611
     [<00000000ce5e0fdd>] __do_sys_write fs/read_write.c:623 [inline]
     [<00000000ce5e0fdd>] __se_sys_write fs/read_write.c:620 [inline]
     [<00000000ce5e0fdd>] __x64_sys_write+0x1e/0x30 fs/read_write.c:620
     [<00000000d9d7b370>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:296
     [<0000000006e6d506>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811d0cf800 (size 512):
   comm "syz-executor673", pid 6965, jiffies 4294943430 (age 7.620s)
   hex dump (first 32 bytes):
     06 00 00 00 05 00 00 00 40 00 00 00 00 00 00 00  ........@.......
     40 00 40 00 00 00 00 00 40 00 40 00 00 00 00 00  @.@.....@.@.....
   backtrace:
     [<00000000b9629d4c>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<00000000b9629d4c>] slab_post_alloc_hook mm/slab.h:522 [inline]
     [<00000000b9629d4c>] slab_alloc_node mm/slab.c:3262 [inline]
     [<00000000b9629d4c>] kmem_cache_alloc_node_trace+0x161/0x2f0  
mm/slab.c:3592
     [<00000000a9b92035>] __do_kmalloc_node mm/slab.c:3614 [inline]
     [<00000000a9b92035>] __kmalloc_node_track_caller+0x38/0x50  
mm/slab.c:3629
     [<00000000fad050db>] __kmalloc_reserve.isra.0+0x40/0xb0  
net/core/skbuff.c:141
     [<00000000a1025904>] __alloc_skb+0xa0/0x210 net/core/skbuff.c:209
     [<000000000167fc45>] alloc_skb include/linux/skbuff.h:1055 [inline]
     [<000000000167fc45>] ppp_write+0x48/0x120  
drivers/net/ppp/ppp_generic.c:502
     [<000000009ab42c0b>] __vfs_write+0x43/0xa0 fs/read_write.c:494
     [<00000000086b2e22>] vfs_write fs/read_write.c:558 [inline]
     [<00000000086b2e22>] vfs_write+0xee/0x210 fs/read_write.c:542
     [<00000000a2b70ef9>] ksys_write+0x7c/0x130 fs/read_write.c:611
     [<00000000ce5e0fdd>] __do_sys_write fs/read_write.c:623 [inline]
     [<00000000ce5e0fdd>] __se_sys_write fs/read_write.c:620 [inline]
     [<00000000ce5e0fdd>] __x64_sys_write+0x1e/0x30 fs/read_write.c:620
     [<00000000d9d7b370>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:296
     [<0000000006e6d506>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: memory leak in ppp_write
  2019-08-29 15:32 ` syzbot
@ 2019-09-12 13:34   ` Takeshi Misawa
  2019-09-12 15:17     ` syzbot
  0 siblings, 1 reply; 4+ messages in thread
From: Takeshi Misawa @ 2019-09-12 13:34 UTC (permalink / raw)
  To: syzbot
  Cc: ast, bpf, daniel, davem, kafai, linux-kernel, linux-ppp, netdev,
	paulus, songliubraving, syzkaller-bugs, yhs

[-- Attachment #1: Type: text/plain, Size: 57 bytes --]

#syz test: https://github.com/google/kasan.git 6525771f


[-- Attachment #2: 0001-ppp-Fix-memory-leak-in-ppp_write.patch --]
[-- Type: text/x-diff, Size: 2454 bytes --]

From e4ff0d04a4b8dd6da3dfb9135235ae5360ce86e6 Mon Sep 17 00:00:00 2001
From: Takeshi Misawa <jeliantsurux@gmail.com>
Date: Wed, 11 Sep 2019 22:18:43 +0900
Subject: [PATCH] ppp: Fix memory leak in ppp_write

When ppp is closing, __ppp_xmit_process() failed to enqueue skb
and skb allocated in ppp_write() is leaked.

syzbot reported :
BUG: memory leak
unreferenced object 0xffff88812a17bc00 (size 224):
  comm "syz-executor673", pid 6952, jiffies 4294942888 (age 13.040s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000d110fff9>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
    [<00000000d110fff9>] slab_post_alloc_hook mm/slab.h:522 [inline]
    [<00000000d110fff9>] slab_alloc_node mm/slab.c:3262 [inline]
    [<00000000d110fff9>] kmem_cache_alloc_node+0x163/0x2f0 mm/slab.c:3574
    [<000000002d616113>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:197
    [<000000000167fc45>] alloc_skb include/linux/skbuff.h:1055 [inline]
    [<000000000167fc45>] ppp_write+0x48/0x120 drivers/net/ppp/ppp_generic.c:502
    [<000000009ab42c0b>] __vfs_write+0x43/0xa0 fs/read_write.c:494
    [<00000000086b2e22>] vfs_write fs/read_write.c:558 [inline]
    [<00000000086b2e22>] vfs_write+0xee/0x210 fs/read_write.c:542
    [<00000000a2b70ef9>] ksys_write+0x7c/0x130 fs/read_write.c:611
    [<00000000ce5e0fdd>] __do_sys_write fs/read_write.c:623 [inline]
    [<00000000ce5e0fdd>] __se_sys_write fs/read_write.c:620 [inline]
    [<00000000ce5e0fdd>] __x64_sys_write+0x1e/0x30 fs/read_write.c:620
    [<00000000d9d7b370>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:296
    [<0000000006e6d506>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by freeing skb, if ppp is closing.

Reported-by: syzbot+d9c8bf24e56416d7ce2c@syzkaller.appspotmail.com
Signed-off-by: Takeshi Misawa <jeliantsurux@gmail.com>
---
 drivers/net/ppp/ppp_generic.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index a30e41a56085..9a1b006904a7 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -1415,6 +1415,8 @@ static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
 			netif_wake_queue(ppp->dev);
 		else
 			netif_stop_queue(ppp->dev);
+	} else {
+		kfree_skb(skb);
 	}
 	ppp_xmit_unlock(ppp);
 }
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: memory leak in ppp_write
  2019-09-12 13:34   ` Takeshi Misawa
@ 2019-09-12 15:17     ` syzbot
  0 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2019-09-12 15:17 UTC (permalink / raw)
  To: ast, bpf, daniel, davem, jeliantsurux, kafai, linux-kernel,
	linux-ppp, netdev, paulus, songliubraving, syzkaller-bugs, yhs

Hello,

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

Reported-and-tested-by:  
syzbot+d9c8bf24e56416d7ce2c@syzkaller.appspotmail.com

Tested on:

commit:         6525771f Merge tag 'arc-5.3-rc7' of git://git.kernel.org/p..
git tree:       https://github.com/google/kasan.git
kernel config:  https://syzkaller.appspot.com/x/.config?x=e6131eafb9408877
dashboard link: https://syzkaller.appspot.com/bug?extid=d9c8bf24e56416d7ce2c
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12610ef1600000

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

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-09-12 15:17 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-05 12:38 memory leak in ppp_write syzbot
2019-08-29 15:32 ` syzbot
2019-09-12 13:34   ` Takeshi Misawa
2019-09-12 15:17     ` syzbot

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