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    io_uring: fix memleak in io_init_wq_offload() · 362a9e65
    Yang Yingliang 提交于
    I got memory leak report when doing fuzz test:
    
    BUG: memory leak
    unreferenced object 0xffff888107310a80 (size 96):
    comm "syz-executor.6", pid 4610, jiffies 4295140240 (age 20.135s)
    hex dump (first 32 bytes):
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
    00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N..........
    backtrace:
    [<000000001974933b>] kmalloc include/linux/slab.h:591 [inline]
    [<000000001974933b>] kzalloc include/linux/slab.h:721 [inline]
    [<000000001974933b>] io_init_wq_offload fs/io_uring.c:7920 [inline]
    [<000000001974933b>] io_uring_alloc_task_context+0x466/0x640 fs/io_uring.c:7955
    [<0000000039d0800d>] __io_uring_add_tctx_node+0x256/0x360 fs/io_uring.c:9016
    [<000000008482e78c>] io_uring_add_tctx_node fs/io_uring.c:9052 [inline]
    [<000000008482e78c>] __do_sys_io_uring_enter fs/io_uring.c:9354 [inline]
    [<000000008482e78c>] __se_sys_io_uring_enter fs/io_uring.c:9301 [inline]
    [<000000008482e78c>] __x64_sys_io_uring_enter+0xabc/0xc20 fs/io_uring.c:9301
    [<00000000b875f18f>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<00000000b875f18f>] do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
    [<000000006b0a8484>] entry_SYSCALL_64_after_hwframe+0x44/0xae
    
    CPU0                          CPU1
    io_uring_enter                io_uring_enter
    io_uring_add_tctx_node        io_uring_add_tctx_node
    __io_uring_add_tctx_node      __io_uring_add_tctx_node
    io_uring_alloc_task_context   io_uring_alloc_task_context
    io_init_wq_offload            io_init_wq_offload
    hash = kzalloc                hash = kzalloc
    ctx->hash_map = hash          ctx->hash_map = hash <- one of the hash is leaked
    
    When calling io_uring_enter() in parallel, the 'hash_map' will be leaked,
    add uring_lock to protect 'hash_map'.
    
    Fixes: e941894e ("io-wq: make buffered file write hashed work map per-ctx")
    Reported-by: NHulk Robot <hulkci@huawei.com>
    Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
    Reviewed-by: NPavel Begunkov <asml.silence@gmail.com>
    Link: https://lore.kernel.org/r/20210720083805.3030730-1-yangyingliang@huawei.comSigned-off-by: NJens Axboe <axboe@kernel.dk>
    362a9e65
io_uring.c 251.4 KB