Re: [PATCH 3/3] i2ctransfer: Zero out memory passed to ioctl()

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

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On Tue, May 13, 2025 at 05:35:39PM +0200, Jean Delvare wrote:
> Valgrind complains that uninitialized memory may be passed to
> ioctl():
> 
> == Syscall param ioctl(I2C_RDWR) points to uninitialised byte(s)
> ==    at 0x499382B: ioctl (in /lib64/libc.so.6)
> ==    by 0x401957: main (i2ctransfer.c:343)
> ==  Address 0x1ffefff94c is on thread 1's stack
> ==  in frame #1, created by main (i2ctransfer.c:144)
> == 
> == Syscall param ioctl(I2C_RDWR).msgs points to uninitialised byte(s)
> ==    at 0x499382B: ioctl (in /lib64/libc.so.6)
> ==    by 0x401957: main (i2ctransfer.c:343)
> ==  Address 0x1ffefff956 is on thread 1's stack
> ==  in frame #1, created by main (i2ctransfer.c:144)
> 
> Zero out the i2c_rdwr_ioctl_data struct as well as the msgs array to
> guarantee that no uninitialized memory will ever be passed to the
> kernel.
> 
> Signed-off-by: Jean Delvare <jdelvare@suse.de>

Applied, thanks!

> This one is not strictly needed, I can't see any actual bug. However
> making valgrind happy seems to be a sane goal, so that we can keep
> using it when debugging other issues without getting distracted.
> Wolfram, what do you think?

Sure, I agree. Also, I like the simpler code.


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