From 32832a407a7178eec3215fad9b1a3298c14b0d69 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Fri, 21 Jul 2023 17:24:31 +0200 Subject: io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area() The io_uring testcase is broken on IA-64 since commit d808459b2e31 ("io_uring: Adjust mapping wrt architecture aliasing requirements"). The reason is, that this commit introduced an own architecture independend get_unmapped_area() search algorithm which finds on IA-64 a memory region which is outside of the regular memory region used for shared userspace mappings and which can't be used on that platform due to aliasing. To avoid similar problems on IA-64 and other platforms in the future, it's better to switch back to the architecture-provided get_unmapped_area() function and adjust the needed input parameters before the call. Beside fixing the issue, the function now becomes easier to understand and maintain. This patch has been successfully tested with the io_uring testcase on physical x86-64, ppc64le, IA-64 and PA-RISC machines. On PA-RISC the LTP mmmap testcases did not report any regressions. Cc: stable@vger.kernel.org # 6.4 Signed-off-by: Helge Deller Reported-by: matoro Fixes: d808459b2e31 ("io_uring: Adjust mapping wrt architecture aliasing requirements") Link: https://lore.kernel.org/r/20230721152432.196382-2-deller@gmx.de Signed-off-by: Jens Axboe --- arch/parisc/kernel/sys_parisc.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'arch') diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c index 39acccabf2ed..465b7cb9d44f 100644 --- a/arch/parisc/kernel/sys_parisc.c +++ b/arch/parisc/kernel/sys_parisc.c @@ -26,12 +26,17 @@ #include /* - * Construct an artificial page offset for the mapping based on the physical + * Construct an artificial page offset for the mapping based on the virtual * address of the kernel file mapping variable. + * If filp is zero the calculated pgoff value aliases the memory of the given + * address. This is useful for io_uring where the mapping shall alias a kernel + * address and a userspace adress where both the kernel and the userspace + * access the same memory region. */ -#define GET_FILP_PGOFF(filp) \ - (filp ? (((unsigned long) filp->f_mapping) >> 8) \ - & ((SHM_COLOUR-1) >> PAGE_SHIFT) : 0UL) +#define GET_FILP_PGOFF(filp, addr) \ + ((filp ? (((unsigned long) filp->f_mapping) >> 8) \ + & ((SHM_COLOUR-1) >> PAGE_SHIFT) : 0UL) \ + + (addr >> PAGE_SHIFT)) static unsigned long shared_align_offset(unsigned long filp_pgoff, unsigned long pgoff) @@ -111,7 +116,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, do_color_align = 0; if (filp || (flags & MAP_SHARED)) do_color_align = 1; - filp_pgoff = GET_FILP_PGOFF(filp); + filp_pgoff = GET_FILP_PGOFF(filp, addr); if (flags & MAP_FIXED) { /* Even MAP_FIXED mappings must reside within TASK_SIZE */ -- cgit v1.2.3-58-ga151