From c51bc12d06b3a5494fbfcbd788a8e307932a06e9 Mon Sep 17 00:00:00 2001 From: Doug Berger Date: Mon, 1 Jul 2019 18:50:11 +0100 Subject: ARM: 8874/1: mm: only adjust sections of valid mm structures A timing hazard exists when an early fork/exec thread begins exiting and sets its mm pointer to NULL while a separate core tries to update the section information. This commit ensures that the mm pointer is not NULL before setting its section parameters. The arguments provided by commit 11ce4b33aedc ("ARM: 8672/1: mm: remove tasklist locking from update_sections_early()") are equally valid for not requiring grabbing the task_lock around this check. Fixes: 08925c2f124f ("ARM: 8464/1: Update all mm structures with section adjustments") Signed-off-by: Doug Berger Acked-by: Laura Abbott Cc: Mike Rapoport Cc: Andrew Morton Cc: Florian Fainelli Cc: Rob Herring Cc: "Steven Rostedt (VMware)" Cc: Peng Fan Cc: Geert Uytterhoeven Signed-off-by: Russell King --- arch/arm/mm/init.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/arm/mm/init.c') diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 16d373d587c4..3a65ded832df 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -628,7 +628,8 @@ static void update_sections_early(struct section_perm perms[], int n) if (t->flags & PF_KTHREAD) continue; for_each_thread(t, s) - set_section_perms(perms, n, true, s->mm); + if (s->mm) + set_section_perms(perms, n, true, s->mm); } set_section_perms(perms, n, true, current->active_mm); set_section_perms(perms, n, true, &init_mm); -- cgit v1.2.3-59-g8ed1b From 5b3efa4f1479c91cb8361acef55f9c6662feba57 Mon Sep 17 00:00:00 2001 From: zhaoyang Date: Mon, 26 Aug 2019 04:07:37 +0100 Subject: ARM: 8901/1: add a criteria for pfn_valid of arm pfn_valid can be wrong when parsing a invalid pfn whose phys address exceeds BITS_PER_LONG as the MSB will be trimed when shifted. The issue originally arise from bellowing call stack, which corresponding to an access of the /proc/kpageflags from userspace with a invalid pfn parameter and leads to kernel panic. [46886.723249] c7 [] (stable_page_flags) from [] [46886.723264] c7 [] (kpageflags_read) from [] [46886.723280] c7 [] (proc_reg_read) from [] [46886.723290] c7 [] (__vfs_read) from [] [46886.723301] c7 [] (vfs_read) from [] [46886.723315] c7 [] (SyS_pread64) from [] (ret_fast_syscall+0x0/0x28) Signed-off-by: Zhaoyang Huang Signed-off-by: Russell King --- arch/arm/mm/init.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/arm/mm/init.c') diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 3a65ded832df..b4be3baa83d4 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -175,6 +175,11 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max_low, #ifdef CONFIG_HAVE_ARCH_PFN_VALID int pfn_valid(unsigned long pfn) { + phys_addr_t addr = __pfn_to_phys(pfn); + + if (__phys_to_pfn(addr) != pfn) + return 0; + return memblock_is_map_memory(__pfn_to_phys(pfn)); } EXPORT_SYMBOL(pfn_valid); -- cgit v1.2.3-59-g8ed1b