lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Sat, 19 Dec 2020 11:12:10 +0100
From:   Mike Galbraith <>
To:     LKML <>
Cc:     linux-mm <>,
        Barry Song <>,
        Vitaly Wool <>,
        Sebastian Andrzej Siewior <>
Subject: Re: [patch] zswap: fix zswap_frontswap_load() vs
 zsmalloc::map/unmap() might_sleep() splat

(mailer partially munged formatting? resend)

mm/zswap: fix zswap_frontswap_load() vs zsmalloc::map/unmap() might_sleep() splat

zsmalloc map/unmap methods use preemption disabling bit spinlocks.  Take the
mutex outside of pool map/unmap methods in zswap_frontswap_load() as is done
in zswap_frontswap_store().

Signed-off-by: Mike Galbraith <>
Fixes: 1ec3b5fe6eec "mm/zswap: move to use crypto_acomp API for hardware acceleration"
 mm/zswap.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1258,20 +1258,20 @@ static int zswap_frontswap_load(unsigned

 	/* decompress */
 	dlen = PAGE_SIZE;
+	acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
+	mutex_lock(acomp_ctx->mutex);
 	src = zpool_map_handle(entry->pool->zpool, entry->handle, ZPOOL_MM_RO);
 	if (zpool_evictable(entry->pool->zpool))
 		src += sizeof(struct zswap_header);

-	acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx);
-	mutex_lock(acomp_ctx->mutex);
 	sg_init_one(&input, src, entry->length);
 	sg_init_table(&output, 1);
 	sg_set_page(&output, page, PAGE_SIZE, 0);
 	acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, dlen);
 	ret = crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait);
-	mutex_unlock(acomp_ctx->mutex);

 	zpool_unmap_handle(entry->pool->zpool, entry->handle);
+	mutex_unlock(acomp_ctx->mutex);


Powered by blists - more mailing lists