Unhandled exception: Load access fault #127
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MichaIng
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[ Upstream commit c0e8246 ] memset() description in ISO/IEC 9899:1999 (and elsewhere) says: The memset function copies the value of c (converted to an unsigned char) into each of the first n characters of the object pointed to by s. The kernel's arm32 memset does not cast c to unsigned char. This results in the following code to produce erroneous output: char a[128]; memset(a, -128, sizeof(a)); This is because gcc will generally emit the following code before it calls memset() : mov r0, r7 mvn r1, starfive-tech#127 ; 0x7f bl 00000000 <memset> r1 ends up with 0xffffff80 before being used by memset() and the 'a' array will have -128 once in every four bytes while the other bytes will be set incorrectly to -1 like this (printing the first 8 bytes) : test_module: -128 -1 -1 -1 test_module: -1 -1 -1 -128 The change here is to 'and' r1 with 255 before it is used. Fixes: 1da177e ("Linux-2.6.12-rc2") Reviewed-by: Ard Biesheuvel <[email protected]> Reviewed-by: Linus Walleij <[email protected]> Signed-off-by: Kursad Oney <[email protected]> Signed-off-by: Russell King (Oracle) <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
MichaIng
pushed a commit
to MichaIng/linux
that referenced
this issue
Nov 29, 2023
[ Upstream commit c0e8246 ] memset() description in ISO/IEC 9899:1999 (and elsewhere) says: The memset function copies the value of c (converted to an unsigned char) into each of the first n characters of the object pointed to by s. The kernel's arm32 memset does not cast c to unsigned char. This results in the following code to produce erroneous output: char a[128]; memset(a, -128, sizeof(a)); This is because gcc will generally emit the following code before it calls memset() : mov r0, r7 mvn r1, starfive-tech#127 ; 0x7f bl 00000000 <memset> r1 ends up with 0xffffff80 before being used by memset() and the 'a' array will have -128 once in every four bytes while the other bytes will be set incorrectly to -1 like this (printing the first 8 bytes) : test_module: -128 -1 -1 -1 test_module: -1 -1 -1 -128 The change here is to 'and' r1 with 255 before it is used. Fixes: 1da177e ("Linux-2.6.12-rc2") Reviewed-by: Ard Biesheuvel <[email protected]> Reviewed-by: Linus Walleij <[email protected]> Signed-off-by: Kursad Oney <[email protected]> Signed-off-by: Russell King (Oracle) <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
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Hello together,
i get the follwing error with the actual upstream Branch from here:
Any solution or tips for that ?
Best regards
Damian
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