From 8032bf1233a74627ce69b803608e650f3f35971c Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Sun, 9 Oct 2022 20:44:02 -0600 Subject: treewide: use get_random_u32_below() instead of deprecated function This is a simple mechanical transformation done by: @@ expression E; @@ - prandom_u32_max + get_random_u32_below (E) Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Acked-by: Darrick J. Wong # for xfs Reviewed-by: SeongJae Park # for damon Reviewed-by: Jason Gunthorpe # for infiniband Reviewed-by: Russell King (Oracle) # for arm Acked-by: Ulf Hansson # for mmc Signed-off-by: Jason A. Donenfeld --- lib/fault-inject.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/fault-inject.c') diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 96e092de5b72..9f53408c545d 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -139,7 +139,7 @@ bool should_fail(struct fault_attr *attr, ssize_t size) return false; } - if (attr->probability <= prandom_u32_max(100)) + if (attr->probability <= get_random_u32_below(100)) return false; if (!fail_stacktrace(attr)) -- cgit v1.2.3 From ea4452de2ae987342fadbdd2c044034e6480daad Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Fri, 18 Nov 2022 18:00:11 +0800 Subject: mm: fix unexpected changes to {failslab|fail_page_alloc}.attr When we specify __GFP_NOWARN, we only expect that no warnings will be issued for current caller. But in the __should_failslab() and __should_fail_alloc_page(), the local GFP flags alter the global {failslab|fail_page_alloc}.attr, which is persistent and shared by all tasks. This is not what we expected, let's fix it. [akpm@linux-foundation.org: unexport should_fail_ex()] Link: https://lkml.kernel.org/r/20221118100011.2634-1-zhengqi.arch@bytedance.com Fixes: 3f913fc5f974 ("mm: fix missing handler for __GFP_NOWARN") Signed-off-by: Qi Zheng Reported-by: Dmitry Vyukov Reviewed-by: Akinobu Mita Reviewed-by: Jason Gunthorpe Cc: Akinobu Mita Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton --- include/linux/fault-inject.h | 7 +++++-- lib/fault-inject.c | 13 ++++++++----- mm/failslab.c | 12 ++++++++++-- mm/page_alloc.c | 7 +++++-- 4 files changed, 28 insertions(+), 11 deletions(-) (limited to 'lib/fault-inject.c') diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h index 9f6e25467844..444236dadcf0 100644 --- a/include/linux/fault-inject.h +++ b/include/linux/fault-inject.h @@ -20,7 +20,6 @@ struct fault_attr { atomic_t space; unsigned long verbose; bool task_filter; - bool no_warn; unsigned long stacktrace_depth; unsigned long require_start; unsigned long require_end; @@ -32,6 +31,10 @@ struct fault_attr { struct dentry *dname; }; +enum fault_flags { + FAULT_NOWARN = 1 << 0, +}; + #define FAULT_ATTR_INITIALIZER { \ .interval = 1, \ .times = ATOMIC_INIT(1), \ @@ -40,11 +43,11 @@ struct fault_attr { .ratelimit_state = RATELIMIT_STATE_INIT_DISABLED, \ .verbose = 2, \ .dname = NULL, \ - .no_warn = false, \ } #define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER int setup_fault_attr(struct fault_attr *attr, char *str); +bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags); bool should_fail(struct fault_attr *attr, ssize_t size); #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 96e092de5b72..adb2f9355ee6 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -41,9 +41,6 @@ EXPORT_SYMBOL_GPL(setup_fault_attr); static void fail_dump(struct fault_attr *attr) { - if (attr->no_warn) - return; - if (attr->verbose > 0 && __ratelimit(&attr->ratelimit_state)) { printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure.\n" "name %pd, interval %lu, probability %lu, " @@ -103,7 +100,7 @@ static inline bool fail_stacktrace(struct fault_attr *attr) * http://www.nongnu.org/failmalloc/ */ -bool should_fail(struct fault_attr *attr, ssize_t size) +bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags) { if (in_task()) { unsigned int fail_nth = READ_ONCE(current->fail_nth); @@ -146,13 +143,19 @@ bool should_fail(struct fault_attr *attr, ssize_t size) return false; fail: - fail_dump(attr); + if (!(flags & FAULT_NOWARN)) + fail_dump(attr); if (atomic_read(&attr->times) != -1) atomic_dec_not_zero(&attr->times); return true; } + +bool should_fail(struct fault_attr *attr, ssize_t size) +{ + return should_fail_ex(attr, size, 0); +} EXPORT_SYMBOL_GPL(should_fail); #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS diff --git a/mm/failslab.c b/mm/failslab.c index 58df9789f1d2..ffc420c0e767 100644 --- a/mm/failslab.c +++ b/mm/failslab.c @@ -16,6 +16,8 @@ static struct { bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags) { + int flags = 0; + /* No fault-injection for bootstrap cache */ if (unlikely(s == kmem_cache)) return false; @@ -30,10 +32,16 @@ bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags) if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB)) return false; + /* + * In some cases, it expects to specify __GFP_NOWARN + * to avoid printing any information(not just a warning), + * thus avoiding deadlocks. See commit 6b9dbedbe349 for + * details. + */ if (gfpflags & __GFP_NOWARN) - failslab.attr.no_warn = true; + flags |= FAULT_NOWARN; - return should_fail(&failslab.attr, s->object_size); + return should_fail_ex(&failslab.attr, s->object_size, flags); } static int __init setup_failslab(char *str) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 218b28ee49ed..6e60657875d3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3887,6 +3887,8 @@ __setup("fail_page_alloc=", setup_fail_page_alloc); static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) { + int flags = 0; + if (order < fail_page_alloc.min_order) return false; if (gfp_mask & __GFP_NOFAIL) @@ -3897,10 +3899,11 @@ static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) (gfp_mask & __GFP_DIRECT_RECLAIM)) return false; + /* See comment in __should_failslab() */ if (gfp_mask & __GFP_NOWARN) - fail_page_alloc.attr.no_warn = true; + flags |= FAULT_NOWARN; - return should_fail(&fail_page_alloc.attr, 1 << order); + return should_fail_ex(&fail_page_alloc.attr, 1 << order, flags); } #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS -- cgit v1.2.3 From 4acb9e5139f20c79eb08a95dc5a28186ae7a5088 Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Wed, 17 Aug 2022 08:03:30 +0000 Subject: fault-injection: skip stacktrace filtering by default If FAULT_INJECTION_STACKTRACE_FILTER is enabled, the depth is default to 32. This means fail_stacktrace() will iter each entry's stacktrace, even if filter is not configured. This patch changes to quick return from fail_stacktrace() if stacktrace filter is not set. Link: https://lkml.kernel.org/r/20220817080332.1052710-3-weiyongjun1@huawei.com Signed-off-by: Wei Yongjun Cc: Akinobu Mita Cc: Dan Williams Cc: Isabella Basso Cc: Josh Poimboeuf Cc: Kees Cook Cc: Miguel Ojeda Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Rasmus Villemoes Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- lib/fault-inject.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/fault-inject.c') diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 1421818c9ef7..fecc4d8ca32a 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -71,7 +71,7 @@ static bool fail_stacktrace(struct fault_attr *attr) int n, nr_entries; bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); - if (depth == 0) + if (depth == 0 || (found && !attr->reject_start && !attr->reject_end)) return found; nr_entries = stack_trace_save(entries, depth, 1); -- cgit v1.2.3 From 0199907474d402809319ada802b50643625914f9 Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Wed, 17 Aug 2022 08:03:31 +0000 Subject: fault-injection: make some stack filter attrs more readable Attributes of stack filter are show as unsigned decimal, such as 'require-start', 'require-end'. This patch change to show them as unsigned hexadecimal for more readable. Before: $ echo 0xffffffffc0257000 > /sys/kernel/debug/failslab/require-start $ cat /sys/kernel/debug/failslab/require-start 18446744072638263296 After: $ echo 0xffffffffc0257000 > /sys/kernel/debug/failslab/require-start $ cat /sys/kernel/debug/failslab/require-start 0xffffffffc0257000 [wangyufen@huawei.com: use debugfs_create_xul() instead of debugfs_create_xl()] Link: https://lkml.kernel.org/r/1664331299-4976-1-git-send-email-wangyufen@huawei.com Link: https://lkml.kernel.org/r/20220817080332.1052710-4-weiyongjun1@huawei.com Signed-off-by: Wei Yongjun Signed-off-by: Wang Yufen Reviewed-by: Akinobu Mita Cc: Dan Williams Cc: Isabella Basso Cc: Josh Poimboeuf Cc: Kees Cook Cc: Miguel Ojeda Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Rasmus Villemoes Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- lib/fault-inject.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'lib/fault-inject.c') diff --git a/lib/fault-inject.c b/lib/fault-inject.c index fecc4d8ca32a..d7819cacf890 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -226,10 +226,10 @@ struct dentry *fault_create_debugfs_attr(const char *name, #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir, &attr->stacktrace_depth); - debugfs_create_ul("require-start", mode, dir, &attr->require_start); - debugfs_create_ul("require-end", mode, dir, &attr->require_end); - debugfs_create_ul("reject-start", mode, dir, &attr->reject_start); - debugfs_create_ul("reject-end", mode, dir, &attr->reject_end); + debugfs_create_xul("require-start", mode, dir, &attr->require_start); + debugfs_create_xul("require-end", mode, dir, &attr->require_end); + debugfs_create_xul("reject-start", mode, dir, &attr->reject_start); + debugfs_create_xul("reject-end", mode, dir, &attr->reject_end); #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ attr->dname = dget(dir); -- cgit v1.2.3 From f9eeef5918bbe1f2545d36280330dced25d6cf97 Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Wed, 17 Aug 2022 08:03:32 +0000 Subject: fault-injection: make stacktrace filter works as expected stacktrace filter is checked after others, such as fail-nth, interval and probability. This make it doesn't work well as expected. Fix to running stacktrace filter before other filters. It will speed up fault inject testing for driver modules. Link: https://lkml.kernel.org/r/20220817080332.1052710-5-weiyongjun1@huawei.com Signed-off-by: Wei Yongjun Cc: Akinobu Mita Cc: Dan Williams Cc: Isabella Basso Cc: Josh Poimboeuf Cc: Kees Cook Cc: Miguel Ojeda Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Rasmus Villemoes Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- lib/fault-inject.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'lib/fault-inject.c') diff --git a/lib/fault-inject.c b/lib/fault-inject.c index d7819cacf890..6cff320c4eb4 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -102,10 +102,16 @@ static inline bool fail_stacktrace(struct fault_attr *attr) bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags) { + bool stack_checked = false; + if (in_task()) { unsigned int fail_nth = READ_ONCE(current->fail_nth); if (fail_nth) { + if (!fail_stacktrace(attr)) + return false; + + stack_checked = true; fail_nth--; WRITE_ONCE(current->fail_nth, fail_nth); if (!fail_nth) @@ -125,6 +131,9 @@ bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags) if (atomic_read(&attr->times) == 0) return false; + if (!stack_checked && !fail_stacktrace(attr)) + return false; + if (atomic_read(&attr->space) > size) { atomic_sub(size, &attr->space); return false; @@ -139,9 +148,6 @@ bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags) if (attr->probability <= get_random_u32_below(100)) return false; - if (!fail_stacktrace(attr)) - return false; - fail: if (!(flags & FAULT_NOWARN)) fail_dump(attr); -- cgit v1.2.3