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Date: Sun, 31 Dec 2023 19:07:04 -0800
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Subject: Re: [syzbot] [dri?] [media?] memory leak in get_sg_table
From: syzbot <syzbot+9b4adfed366b14496e7e@syzkaller.appspotmail.com>
To: eadavis@qq.com, linux-kernel@vger.kernel.org, 
	syzkaller-bugs@googlegroups.com
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Hello,

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

2024/01/01 02:58:28 executed programs: 1
BUG: memory leak
unreferenced object 0xffff88811b080600 (size 16):
  comm "syz-executor.0", pid 5492, jiffies 4294944266 (age 13.620s)
  hex dump (first 16 bytes):
    80 22 25 1b 81 88 ff ff 04 00 00 00 04 00 00 00  ."%.............
  backtrace:
    [<ffffffff816346ed>] kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline]
    [<ffffffff816346ed>] slab_post_alloc_hook mm/slab.h:766 [inline]
    [<ffffffff816346ed>] slab_alloc_node mm/slub.c:3478 [inline]
    [<ffffffff816346ed>] __kmem_cache_alloc_node+0x2dd/0x3f0 mm/slub.c:3517
    [<ffffffff8157f315>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1098
    [<ffffffff82cfd82a>] kmalloc include/linux/slab.h:600 [inline]
    [<ffffffff82cfd82a>] kzalloc include/linux/slab.h:721 [inline]
    [<ffffffff82cfd82a>] get_sg_table.isra.0+0x2a/0xe0 drivers/dma-buf/udmabuf.c:93
    [<ffffffff82cfd986>] begin_cpu_udmabuf+0x76/0xb0 drivers/dma-buf/udmabuf.c:157
    [<ffffffff82cf114b>] dma_buf_begin_cpu_access+0x3b/0xc0 drivers/dma-buf/dma-buf.c:1405
    [<ffffffff82cf1bd4>] dma_buf_ioctl+0x394/0x690 drivers/dma-buf/dma-buf.c:477
    [<ffffffff816bf4a2>] vfs_ioctl fs/ioctl.c:51 [inline]
    [<ffffffff816bf4a2>] __do_sys_ioctl fs/ioctl.c:871 [inline]
    [<ffffffff816bf4a2>] __se_sys_ioctl fs/ioctl.c:857 [inline]
    [<ffffffff816bf4a2>] __x64_sys_ioctl+0xf2/0x140 fs/ioctl.c:857
    [<ffffffff84b71e2f>] do_syscall_x64 arch/x86/entry/common.c:52 [inline]
    [<ffffffff84b71e2f>] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:83
    [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0x6b

BUG: memory leak
unreferenced object 0xffff88811b252280 (size 128):
  comm "syz-executor.0", pid 5492, jiffies 4294944266 (age 13.620s)
  hex dump (first 32 bytes):
    00 b1 52 04 00 ea ff ff 00 00 00 00 00 10 00 00  ..R.............
    00 40 ac 14 01 00 00 00 00 10 00 00 00 00 00 00  .@..............
  backtrace:
    [<ffffffff816346ed>] kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline]
    [<ffffffff816346ed>] slab_post_alloc_hook mm/slab.h:766 [inline]
    [<ffffffff816346ed>] slab_alloc_node mm/slub.c:3478 [inline]
    [<ffffffff816346ed>] __kmem_cache_alloc_node+0x2dd/0x3f0 mm/slub.c:3517
    [<ffffffff8157f9bb>] __do_kmalloc_node mm/slab_common.c:1006 [inline]
    [<ffffffff8157f9bb>] __kmalloc+0x4b/0x150 mm/slab_common.c:1020
    [<ffffffff8251661f>] kmalloc_array include/linux/slab.h:637 [inline]
    [<ffffffff8251661f>] sg_kmalloc lib/scatterlist.c:167 [inline]
    [<ffffffff8251661f>] get_next_sg lib/scatterlist.c:402 [inline]
    [<ffffffff8251661f>] sg_alloc_append_table_from_pages+0x35f/0x770 lib/scatterlist.c:526
    [<ffffffff82516abc>] sg_alloc_table_from_pages_segment+0x8c/0x120 lib/scatterlist.c:586
    [<ffffffff82cfd85e>] sg_alloc_table_from_pages include/linux/scatterlist.h:477 [inline]
    [<ffffffff82cfd85e>] get_sg_table.isra.0+0x5e/0xe0 drivers/dma-buf/udmabuf.c:96
    [<ffffffff82cfd986>] begin_cpu_udmabuf+0x76/0xb0 drivers/dma-buf/udmabuf.c:157
    [<ffffffff82cf114b>] dma_buf_begin_cpu_access+0x3b/0xc0 drivers/dma-buf/dma-buf.c:1405
    [<ffffffff82cf1bd4>] dma_buf_ioctl+0x394/0x690 drivers/dma-buf/dma-buf.c:477
    [<ffffffff816bf4a2>] vfs_ioctl fs/ioctl.c:51 [inline]
    [<ffffffff816bf4a2>] __do_sys_ioctl fs/ioctl.c:871 [inline]
    [<ffffffff816bf4a2>] __se_sys_ioctl fs/ioctl.c:857 [inline]
    [<ffffffff816bf4a2>] __x64_sys_ioctl+0xf2/0x140 fs/ioctl.c:857
    [<ffffffff84b71e2f>] do_syscall_x64 arch/x86/entry/common.c:52 [inline]
    [<ffffffff84b71e2f>] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:83
    [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0x6b


Tested on:

commit:         fbafc3e6 Merge tag 'for_linus' of git://git.kernel.org..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13cf2909e80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e81921f96ae24ec0
dashboard link: https://syzkaller.appspot.com/bug?extid=9b4adfed366b14496e7e
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14778665e80000