Revision 3808d34838184fd29088d6b3a364ba2f1c018fb6 authored by Stanislaw Gruszka on 02 February 2017, 12:32:10 UTC, committed by David S. Miller on 03 February 2017, 16:13:00 UTC
If ->get_regs_len() callback return 0, we allocate 0 bytes of memory, what print ugly warning in dmesg, which can be found further below. This happen on mac80211 devices where ieee80211_get_regs_len() just return 0 and driver only fills ethtool_regs structure and actually do not provide any dump. However I assume this can happen on other drivers i.e. when for some devices driver provide regs dump and for others do not. Hence preventing to to print warning in ethtool code seems to be reasonable. ethtool: vmalloc: allocation failure: 0 bytes, mode:0x24080c2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO) <snip> Call Trace: [<ffffffff813bde47>] dump_stack+0x63/0x8c [<ffffffff811b0a1f>] warn_alloc+0x13f/0x170 [<ffffffff811f0476>] __vmalloc_node_range+0x1e6/0x2c0 [<ffffffff811f0874>] vzalloc+0x54/0x60 [<ffffffff8169986c>] dev_ethtool+0xb4c/0x1b30 [<ffffffff816adbb1>] dev_ioctl+0x181/0x520 [<ffffffff816714d2>] sock_do_ioctl+0x42/0x50 <snip> Mem-Info: active_anon:435809 inactive_anon:173951 isolated_anon:0 active_file:835822 inactive_file:196932 isolated_file:0 unevictable:0 dirty:8 writeback:0 unstable:0 slab_reclaimable:157732 slab_unreclaimable:10022 mapped:83042 shmem:306356 pagetables:9507 bounce:0 free:130041 free_pcp:1080 free_cma:0 Node 0 active_anon:1743236kB inactive_anon:695804kB active_file:3343288kB inactive_file:787728kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:332168kB dirty:32kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 1225424kB writeback_tmp:0kB unstable:0kB pages_scanned:0 all_unreclaimable? no Node 0 DMA free:15900kB min:136kB low:168kB high:200kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15984kB managed:15900kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB lowmem_reserve[]: 0 3187 7643 7643 Node 0 DMA32 free:419732kB min:28124kB low:35152kB high:42180kB active_anon:541180kB inactive_anon:248988kB active_file:1466388kB inactive_file:389632kB unevictable:0kB writepending:0kB present:3370280kB managed:3290932kB mlocked:0kB slab_reclaimable:217184kB slab_unreclaimable:4180kB kernel_stack:160kB pagetables:984kB bounce:0kB free_pcp:2236kB local_pcp:660kB free_cma:0kB lowmem_reserve[]: 0 0 4456 4456 Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Kconfig.kasan
config HAVE_ARCH_KASAN
bool
if HAVE_ARCH_KASAN
config KASAN
bool "KASan: runtime memory debugger"
depends on SLUB || (SLAB && !DEBUG_SLAB)
select CONSTRUCTORS
select STACKDEPOT
help
Enables kernel address sanitizer - runtime memory debugger,
designed to find out-of-bounds accesses and use-after-free bugs.
This is strictly a debugging feature and it requires a gcc version
of 4.9.2 or later. Detection of out of bounds accesses to stack or
global variables requires gcc 5.0 or later.
This feature consumes about 1/8 of available memory and brings about
~x3 performance slowdown.
For better error detection enable CONFIG_STACKTRACE.
Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
(the resulting kernel does not boot).
choice
prompt "Instrumentation type"
depends on KASAN
default KASAN_OUTLINE
config KASAN_OUTLINE
bool "Outline instrumentation"
help
Before every memory access compiler insert function call
__asan_load*/__asan_store*. These functions performs check
of shadow memory. This is slower than inline instrumentation,
however it doesn't bloat size of kernel's .text section so
much as inline does.
config KASAN_INLINE
bool "Inline instrumentation"
help
Compiler directly inserts code checking shadow memory before
memory accesses. This is faster than outline (in some workloads
it gives about x2 boost over outline instrumentation), but
make kernel's .text size much bigger.
This requires a gcc version of 5.0 or later.
endchoice
config TEST_KASAN
tristate "Module for testing kasan for bug detection"
depends on m && KASAN
help
This is a test module doing various nasty things like
out of bounds accesses, use after free. It is useful for testing
kernel debugging features like kernel address sanitizer.
endif
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