On Tue, Aug 29, 2023 at 09:41:32AM -0700, Luis Chamberlain wrote:
On Tue, Aug 29, 2023 at 02:05:08PM +0200, Andrea Righi wrote:Using kmalloc() to allocate the decompression workspace for zstd may trigger the following warning when large modules are loaded (i.e., xfs): [ 2.961884] WARNING: CPU: 1 PID: 254 at mm/page_alloc.c:4453 __alloc_pages+0x2c3/0x350 ... [ 2.989033] Call Trace: [ 2.989841] <TASK> [ 2.990614] ? show_regs+0x6d/0x80 [ 2.991573] ? __warn+0x89/0x160 [ 2.992485] ? __alloc_pages+0x2c3/0x350 [ 2.993520] ? report_bug+0x17e/0x1b0 [ 2.994506] ? handle_bug+0x51/0xa0 [ 2.995474] ? exc_invalid_op+0x18/0x80 [ 2.996469] ? asm_exc_invalid_op+0x1b/0x20 [ 2.997530] ? module_zstd_decompress+0xdc/0x2a0 [ 2.998665] ? __alloc_pages+0x2c3/0x350 [ 2.999695] ? module_zstd_decompress+0xdc/0x2a0 [ 3.000821] __kmalloc_large_node+0x7a/0x150 [ 3.001920] __kmalloc+0xdb/0x170 [ 3.002824] module_zstd_decompress+0xdc/0x2a0 [ 3.003857] module_decompress+0x37/0xc0 [ 3.004688] init_module_from_file+0xd0/0x100 [ 3.005668] idempotent_init_module+0x11c/0x2b0 [ 3.006632] __x64_sys_finit_module+0x64/0xd0 [ 3.007568] do_syscall_64+0x59/0x90 [ 3.008373] ? ksys_read+0x73/0x100 [ 3.009395] ? exit_to_user_mode_prepare+0x30/0xb0 [ 3.010531] ? syscall_exit_to_user_mode+0x37/0x60 [ 3.011662] ? do_syscall_64+0x68/0x90 [ 3.012511] ? do_syscall_64+0x68/0x90 [ 3.013364] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 However, continuous physical memory does not seem to be required in module_zstd_decompress(), so use vmalloc() instead, to prevent the warning and avoid potential failures at loading compressed modules. Fixes: 169a58ad824d ("module/decompress: Support zstd in-kernel decompression") Signed-off-by: Andrea Righi <andrea.righi@xxxxxxxxxxxxx> --- kernel/module/decompress.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/module/decompress.c b/kernel/module/decompress.c index 8a5d6d63b06c..87440f714c0c 100644 --- a/kernel/module/decompress.c +++ b/kernel/module/decompress.c @@ -241,7 +241,7 @@ static ssize_t module_zstd_decompress(struct load_info *info, } wksp_size = zstd_dstream_workspace_bound(header.windowSize); - wksp = kmalloc(wksp_size, GFP_KERNEL); + wksp = vmalloc(wksp_size); if (!wksp) { retval = -ENOMEM; goto out; @@ -284,7 +284,7 @@ static ssize_t module_zstd_decompress(struct load_info *info, retval = new_size; out: - kfree(wksp); + vfree(wksp); return retval;Thanks! Applied and queued up.
I can see at least the gz decompress would need the same kind of change. Shouldn't we tackle them all at once? Lucas De Marchi
Luis
