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lib/stackdepot: add printk_deferred_enter/exit guards

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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@google.com
Link: https://lkml.kernel.org/r/82092f9040d075a161d1264377d51e0bac847e8a.1703020707.git.andreyknvl@google.com
Fixes: 108be8def4 ("lib/stackdepot: allow users to evict stack traces")
Fixes: cd11016e5f ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Closes: https://lore.kernel.org/all/000000000000f56750060b9ad216@google.com/
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2023-12-19 22:19:50 +01:00 committed by Andrew Morton
parent 8ab3b09755
commit a914d8d6cf
1 changed files with 9 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
lib/stackdepot.c
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@ -506,12 +506,14 @@ depot_stack_handle_t stack_depot_save_flags(unsigned long *entries,
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_flags(unsigned long *entries,
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_flags(unsigned long *entries,
}
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_flags(unsigned long *entries,
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_stack_handle_t handle,
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_t 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_t handle)
}
out:
printk_deferred_exit();
write_unlock_irqrestore(&pool_rwlock, flags);
}
EXPORT_SYMBOL_GPL(stack_depot_put);