| Message ID | 20240530142340.1248216-1-leitao@debian.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | io_uring/rw: Free iovec before cleaning async data | expand |
On Thu, 30 May 2024 07:23:39 -0700, Breno Leitao wrote: > kmemleak shows that there is a memory leak in io_uring read operation, > where a buffer is allocated at iovec import, but never de-allocated. > > The memory is allocated at io_async_rw->free_iovec, but, then > io_async_rw is kfreed, taking the allocated memory with it. I saw this > happening when the read operation fails with -11 (EAGAIN). > > [...] Applied, thanks! [1/1] io_uring/rw: Free iovec before cleaning async data commit: e112311615a24e1618a591c73506571dc304eb8d Best regards,
diff --git a/io_uring/opdef.c b/io_uring/opdef.c index 2de5cca9504e..2e3b7b16effb 100644 --- a/io_uring/opdef.c +++ b/io_uring/opdef.c @@ -516,10 +516,12 @@ const struct io_cold_def io_cold_defs[] = { }, [IORING_OP_READ_FIXED] = { .name = "READ_FIXED", + .cleanup = io_readv_writev_cleanup, .fail = io_rw_fail, }, [IORING_OP_WRITE_FIXED] = { .name = "WRITE_FIXED", + .cleanup = io_readv_writev_cleanup, .fail = io_rw_fail, }, [IORING_OP_POLL_ADD] = { @@ -582,10 +584,12 @@ const struct io_cold_def io_cold_defs[] = { }, [IORING_OP_READ] = { .name = "READ", + .cleanup = io_readv_writev_cleanup, .fail = io_rw_fail, }, [IORING_OP_WRITE] = { .name = "WRITE", + .cleanup = io_readv_writev_cleanup, .fail = io_rw_fail, }, [IORING_OP_FADVISE] = { @@ -692,6 +696,7 @@ const struct io_cold_def io_cold_defs[] = { }, [IORING_OP_READ_MULTISHOT] = { .name = "READ_MULTISHOT", + .cleanup = io_readv_writev_cleanup, }, [IORING_OP_WAITID] = { .name = "WAITID",
kmemleak shows that there is a memory leak in io_uring read operation, where a buffer is allocated at iovec import, but never de-allocated. The memory is allocated at io_async_rw->free_iovec, but, then io_async_rw is kfreed, taking the allocated memory with it. I saw this happening when the read operation fails with -11 (EAGAIN). This is the kmemleak splat. unreferenced object 0xffff8881da591c00 (size 256): ... backtrace (crc 7a15bdee): [<00000000256f2de4>] __kmalloc+0x2d6/0x410 [<000000007a9f5fc7>] iovec_from_user.part.0+0xc6/0x160 [<00000000cecdf83a>] __import_iovec+0x50/0x220 [<00000000d1d586a2>] __io_import_iovec+0x13d/0x220 [<0000000054ee9bd2>] io_prep_rw+0x186/0x340 [<00000000a9c0372d>] io_prep_rwv+0x31/0x120 [<000000001d1170b9>] io_prep_readv+0xe/0x30 [<0000000070b8eb67>] io_submit_sqes+0x1bd/0x780 [<00000000812496d4>] __do_sys_io_uring_enter+0x3ed/0x5b0 [<0000000081499602>] do_syscall_64+0x5d/0x170 [<00000000de1c5a4d>] entry_SYSCALL_64_after_hwframe+0x76/0x7e This occurs because the async data cleanup functions are not set for read/write operations. As a result, the potentially allocated iovec in the rw async data is not freed before the async data is released, leading to a memory leak. With this following patch, kmemleak does not show the leaked memory anymore, and all liburing tests pass. Fixes: a9165b83c193 ("io_uring/rw: always setup io_async_rw for read/write requests") Signed-off-by: Breno Leitao <leitao@debian.org> --- io_uring/opdef.c | 5 +++++ 1 file changed, 5 insertions(+)