https://github.com/torvalds/linux
Revision 0646dc31ca886693274df5749cd0c8c1eaaeb5ca authored by Liang Chen on 13 April 2023, 09:03:53 UTC, committed by Jakub Kicinski on 13 April 2023, 17:08:42 UTC
Commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment recycling") allowed coalescing to proceed with non page pool page and page pool page when @from is cloned, i.e. to->pp_recycle --> false from->pp_recycle --> true skb_cloned(from) --> true However, it actually requires skb_cloned(@from) to hold true until coalescing finishes in this situation. If the other cloned SKB is released while the merging is in process, from_shinfo->nr_frags will be set to 0 toward the end of the function, causing the increment of frag page _refcount to be unexpectedly skipped resulting in inconsistent reference counts. Later when SKB(@to) is released, it frees the page directly even though the page pool page is still in use, leading to use-after-free or double-free errors. So it should be prohibited. The double-free error message below prompted us to investigate: BUG: Bad page state in process swapper/1 pfn:0e0d1 page:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000 index:0x2 pfn:0xe0d1 flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000 raw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000 page dumped because: nonzero _refcount CPU: 1 PID: 0 Comm: swapper/1 Tainted: G E 6.2.0+ Call Trace: <IRQ> dump_stack_lvl+0x32/0x50 bad_page+0x69/0xf0 free_pcp_prepare+0x260/0x2f0 free_unref_page+0x20/0x1c0 skb_release_data+0x10b/0x1a0 napi_consume_skb+0x56/0x150 net_rx_action+0xf0/0x350 ? __napi_schedule+0x79/0x90 __do_softirq+0xc8/0x2b1 __irq_exit_rcu+0xb9/0xf0 common_interrupt+0x82/0xa0 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 RIP: 0010:default_idle+0xb/0x20 Fixes: 53e0961da1c7 ("page_pool: add frag page recycling support in page pool") Signed-off-by: Liang Chen <liangchen.linux@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20230413090353.14448-1-liangchen.linux@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
1 parent e8b7445
Tip revision: 0646dc31ca886693274df5749cd0c8c1eaaeb5ca authored by Liang Chen on 13 April 2023, 09:03:53 UTC
skbuff: Fix a race between coalescing and releasing SKBs
skbuff: Fix a race between coalescing and releasing SKBs
Tip revision: 0646dc3
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arch | ||
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certs | ||
crypto | ||
drivers | ||
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init | ||
io_uring | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
rust | ||
samples | ||
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tools | ||
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.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 151 bytes |
.gitattributes | -rw-r--r-- | 90 bytes |
.gitignore | -rw-r--r-- | 2.1 KB |
.mailmap | -rw-r--r-- | 26.8 KB |
.rustfmt.toml | -rw-r--r-- | 369 bytes |
COPYING | -rw-r--r-- | 496 bytes |
CREDITS | -rw-r--r-- | 99.7 KB |
Kbuild | -rw-r--r-- | 2.5 KB |
Kconfig | -rw-r--r-- | 555 bytes |
MAINTAINERS | -rw-r--r-- | 684.8 KB |
Makefile | -rw-r--r-- | 70.0 KB |
README | -rw-r--r-- | 727 bytes |
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