On 2019/1/14 22:05, Sheng Yong wrote:
> When setting /sys/fs/f2fs/<DEV>/iostat_enable with non-boolean value,
> UBSAN reports the following warning.
>
> [ 7562.295484]
> ================================================================================
> [ 7562.296531] UBSAN: Undefined behaviour in fs/f2fs/f2fs.h:2776:10
> [ 7562.297651] load of value 64 is not a valid value for type '_Bool'
> [ 7562.298642] CPU: 1 PID: 7487 Comm: dd Not tainted 4.20.0-rc4+ #79
> [ 7562.298653] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS
> VirtualBox 12/01/2006
> [ 7562.298662] Call Trace:
> [ 7562.298760] dump_stack+0x46/0x5b
> [ 7562.298811] ubsan_epilogue+0x9/0x40
> [ 7562.298830] __ubsan_handle_load_invalid_value+0x72/0x90
> [ 7562.298863] f2fs_file_write_iter+0x29f/0x3f0
> [ 7562.298905] __vfs_write+0x115/0x160
> [ 7562.298922] vfs_write+0xa7/0x190
> [ 7562.298934] ksys_write+0x50/0xc0
> [ 7562.298973] do_syscall_64+0x4a/0xe0
> [ 7562.298992] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [ 7562.299001] RIP: 0033:0x7fa45ec19c00
> [ 7562.299004] Code: 73 01 c3 48 8b 0d 88 92 2c 00 f7 d8 64 89 01 48 83 c8 ff
> c3 66 0f 1f 44 00 00 83 3d dd eb 2c 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d
> 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ce 8f 01 00 48 89 04 24
> [ 7562.299044] RSP: 002b:00007ffca52b49e8 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000001
> [ 7562.299052] RAX: ffffffffffffffda RBX: 0000000000000000 RCX:
> 00007fa45ec19c00
> [ 7562.299059] RDX: 0000000000000400 RSI: 000000000093f000 RDI:
> 0000000000000001
> [ 7562.299065] RBP: 000000000093f000 R08: 0000000000000004 R09:
> 0000000000000000
> [ 7562.299071] R10: 00007ffca52b47b0 R11: 0000000000000246 R12:
> 0000000000000400
> [ 7562.299077] R13: 000000000093f000 R14: 000000000093f400 R15:
> 0000000000000000
> [ 7562.299091]
> ================================================================================
>
> So, if iostat_enable is enabled, set its value as `true'.
>
> Signed-off-by: Sheng Yong <shengyo...@huawei.com>
> ---
> fs/f2fs/sysfs.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index 0575edbe3ed6..b192627742a9 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -278,10 +278,17 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
> return count;
> }
>
> - *ui = t;
>
> - if (!strcmp(a->attr.name, "iostat_enable") && *ui == 0)
> - f2fs_reset_iostat(sbi);
> + if (!strcmp(a->attr.name, "iostat_enable")) {
bool enable = !!*ui;
if (!enable)
f2fs_reset_iostat(sbi);
sbi->iostat_enable = enable;
return count;
> + if (t == 0)
> + f2fs_reset_iostat(sbi);
> + else
> + sbi->iostat_enable = true;
> + return count;
> + }
> +
> + *ui = (unsigned int)t;
> +
> return count;
> }
>
>
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