From 6f4679b956741d2da6ad3ebb738cbe1264ac8781 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Wed, 4 Dec 2019 10:59:09 +0530 Subject: [PATCH] powerpc/pmem: Fix kernel crash due to wrong range value usage in flush_dcache_range This patch fix the below kernel crash. BUG: Unable to handle kernel data access on read at 0xc000000380000000 Faulting instruction address: 0xc00000000008b6f0 cpu 0x5: Vector: 300 (Data Access) at [c0000000d8587790] pc: c00000000008b6f0: arch_remove_memory+0x150/0x210 lr: c00000000008b720: arch_remove_memory+0x180/0x210 sp: c0000000d8587a20 msr: 800000000280b033 dar: c000000380000000 dsisr: 40000000 current = 0xc0000000d8558600 paca = 0xc00000000fff8f00 irqmask: 0x03 irq_happened: 0x01 pid = 1220, comm = ndctl enter ? for help memunmap_pages+0x33c/0x410 devm_action_release+0x30/0x50 release_nodes+0x30c/0x3a0 device_release_driver_internal+0x178/0x240 unbind_store+0x74/0x190 drv_attr_store+0x44/0x60 sysfs_kf_write+0x74/0xa0 kernfs_fop_write+0x1b0/0x260 __vfs_write+0x3c/0x70 vfs_write+0xe4/0x200 ksys_write+0x7c/0x140 system_call+0x5c/0x68 Fixes: 076265907cf9 ("powerpc: Chunk calls to flush_dcache_range in arch_*_memory") Reported-by: Sachin Sant Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191204052909.59145-1-aneesh.kumar@linux.ibm.com --- arch/powerpc/mm/mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index ad299e72ec30..9488b63dfc87 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -121,7 +121,7 @@ static void flush_dcache_range_chunked(unsigned long start, unsigned long stop, unsigned long i; for (i = start; i < stop; i += chunk) { - flush_dcache_range(i, min(stop, start + chunk)); + flush_dcache_range(i, min(stop, i + chunk)); cond_resched(); } }