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From:   "Theodore Ts'o" <tytso@mit.edu>
To:     Gaosheng Cui <cuigaosheng1@huawei.com>, cmaiolino@redhat.com,
        adilger.kernel@dilger.ca
Cc:     "Theodore Ts'o" <tytso@mit.edu>, linux-ext4@vger.kernel.org
Subject: Re: [PATCH] ext4: fix undefined behavior in bit shift for ext4_check_flag_values
Date:   Tue,  6 Dec 2022 16:01:47 -0500
Message-Id: <167036049592.156498.2455997966584803257.b4-ty@mit.edu>
In-Reply-To: <20221031055833.3966222-1-cuigaosheng1@huawei.com>
References: <20221031055833.3966222-1-cuigaosheng1@huawei.com>
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On Mon, 31 Oct 2022 13:58:33 +0800, Gaosheng Cui wrote:
> Shifting signed 32-bit value by 31 bits is undefined, so changing
> significant bit to unsigned. The UBSAN warning calltrace like below:
> 
> UBSAN: shift-out-of-bounds in fs/ext4/ext4.h:591:2
> left shift of 1 by 31 places cannot be represented in type 'int'
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x7d/0xa5
>  dump_stack+0x15/0x1b
>  ubsan_epilogue+0xe/0x4e
>  __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
>  ext4_init_fs+0x5a/0x277
>  do_one_initcall+0x76/0x430
>  kernel_init_freeable+0x3b3/0x422
>  kernel_init+0x24/0x1e0
>  ret_from_fork+0x1f/0x30
>  </TASK>
> 
> [...]

Applied, thanks!

[1/1] ext4: fix undefined behavior in bit shift for ext4_check_flag_values
      commit: 0cd464d06ba0b9941dd285042909dc4d94adb373

Best regards,
-- 
Theodore Ts'o <tytso@mit.edu>