The patch titled
Subject: lib/stackdepot: add printk_deferred_enter/exit guards
has been added to the -mm mm-nonmm-unstable branch. Its filename is
lib-stackdepot-add-printk_deferred_enter-exit-guards.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-stackdepot-add-printk_deferred_enter-exit-guards.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: lib/stackdepot: add printk_deferred_enter/exit guards
Date: Tue, 19 Dec 2023 22:19:50 +0100
Patch series "lib/stackdepot, kasan: fixes for stack eviction series", v3.
A few fixes for the stack depot eviction series ("stackdepot: allow
evicting stack traces").
This patch (of 5):
Stack depot functions can be called from various contexts that do
allocations, including with console locks taken. At the same time, stack
depot functions might print WARNING's or refcount-related failures.
This can cause a deadlock on console locks.
Add printk_deferred_enter/exit guards to stack depot to avoid this.
Link: https://lkml.kernel.org/r/cover.1703020707.git.andreyknvl@xxxxxxxxxx
Link: https://lkml.kernel.org/r/82092f9040d075a161d1264377d51e0bac847e8a.1703020707.git.andreyknvl@xxxxxxxxxx
Fixes: 108be8def46e ("lib/stackdepot: allow users to evict stack traces")
Fixes: cd11016e5f52 ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB")
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Closes: https://lore.kernel.org/all/000000000000f56750060b9ad216@xxxxxxxxxx/
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/stackdepot.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/lib/stackdepot.c~lib-stackdepot-add-printk_deferred_enter-exit-guards
+++ a/lib/stackdepot.c
@@ -506,12 +506,14 @@ depot_stack_handle_t stack_depot_save_fl
bucket = &stack_table[hash & stack_hash_mask];
read_lock_irqsave(&pool_rwlock, flags);
+ printk_deferred_enter();
/* Fast path: look the stack trace up without full locking. */
found = find_stack(bucket, entries, nr_entries, hash);
if (found) {
if (depot_flags & STACK_DEPOT_FLAG_GET)
refcount_inc(&found->count);
+ printk_deferred_exit();
read_unlock_irqrestore(&pool_rwlock, flags);
goto exit;
}
@@ -520,6 +522,7 @@ depot_stack_handle_t stack_depot_save_fl
if (new_pool_required)
need_alloc = true;
+ printk_deferred_exit();
read_unlock_irqrestore(&pool_rwlock, flags);
/*
@@ -541,6 +544,7 @@ depot_stack_handle_t stack_depot_save_fl
}
write_lock_irqsave(&pool_rwlock, flags);
+ printk_deferred_enter();
found = find_stack(bucket, entries, nr_entries, hash);
if (!found) {
@@ -562,6 +566,7 @@ depot_stack_handle_t stack_depot_save_fl
depot_keep_new_pool(&prealloc);
}
+ printk_deferred_exit();
write_unlock_irqrestore(&pool_rwlock, flags);
exit:
if (prealloc) {
@@ -600,9 +605,11 @@ unsigned int stack_depot_fetch(depot_sta
return 0;
read_lock_irqsave(&pool_rwlock, flags);
+ printk_deferred_enter();
stack = depot_fetch_stack(handle);
+ printk_deferred_exit();
read_unlock_irqrestore(&pool_rwlock, flags);
*entries = stack->entries;
@@ -619,6 +626,7 @@ void stack_depot_put(depot_stack_handle_
return;
write_lock_irqsave(&pool_rwlock, flags);
+ printk_deferred_enter();
stack = depot_fetch_stack(handle);
if (WARN_ON(!stack))
@@ -633,6 +641,7 @@ void stack_depot_put(depot_stack_handle_
}
out:
+ printk_deferred_exit();
write_unlock_irqrestore(&pool_rwlock, flags);
}
EXPORT_SYMBOL_GPL(stack_depot_put);
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-rename-kasan_slab_free_mempool-to-kasan_mempool_poison_object.patch
kasan-move-kasan_mempool_poison_object.patch
kasan-document-kasan_mempool_poison_object.patch
kasan-add-return-value-for-kasan_mempool_poison_object.patch
kasan-introduce-kasan_mempool_unpoison_object.patch
kasan-introduce-kasan_mempool_poison_pages.patch
kasan-introduce-kasan_mempool_unpoison_pages.patch
kasan-clean-up-__kasan_mempool_poison_object.patch
kasan-save-free-stack-traces-for-slab-mempools.patch
kasan-clean-up-and-rename-____kasan_kmalloc.patch
kasan-introduce-poison_kmalloc_large_redzone.patch
kasan-save-alloc-stack-traces-for-mempool.patch
mempool-skip-slub_debug-poisoning-when-kasan-is-enabled.patch
mempool-use-new-mempool-kasan-hooks.patch
mempool-introduce-mempool_use_prealloc_only.patch
kasan-add-mempool-tests.patch
kasan-rename-pagealloc-tests.patch
kasan-reorder-tests.patch
kasan-rename-and-document-kasan_unpoison_object_data.patch
skbuff-use-mempool-kasan-hooks.patch
io_uring-use-mempool-kasan-hook.patch
lib-stackdepot-add-printk_deferred_enter-exit-guards.patch
kasan-handle-concurrent-kasan_record_aux_stack-calls.patch
kasan-memset-free-track-in-qlink_free.patch
lib-stackdepot-fix-comment-in-include-linux-stackdepoth.patch
